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Last modified: Tue, 17 Apr 2018
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Triple Feed Patch antenna


The Triple Feed Patch antenna is a directional circularly polarized antenna that I created in collaboration with Robin Theunis, one of my co-workers. The main design goals were:

  • Good radiation efficiency. Most FR4-based patches have terrible efficiency because FR4 is very lossy at 5.8 GHz.

  • Good axial ratio, not just directly perpendicular to the patch but also off-center.

  • Cheap and easy to manufacture with high accuracy, even for a hobbyist.

Image: tfp1-photo1-small.jpg

Photo of a Triple Feed Patch 1 prototype. This is the 'hybrid' variant, which is simultaneously LHCP and RHCP, with a different connector for each polarization. There is a regular single-connector LHCP/RHCP variant as well.

Special thanks to Antenna Test Lab who were kind enough to provide complete spherical anechoic chamber measurements (i.e. 3D radiation patterns) for the Triple Feed Patch antenna. You can find a detailed test report of the Triple Feed Patch antenna on their website.

Specifications

Simulated

Measured

Notes

Center frequency

5.8 GHz

5.8 GHz ± 100 MHz

Bandwidth

660 MHz (5.47 – 6.13 GHz)

800 MHz ± 50 MHz

Feed network losses increase bandwidth

Matching

S11 < -30 dB, VSWR < 1.065

S11 < -20 dB, VSWR < 1.22

At center frequency

Axial ratio

1.13 (1.06 dB)

1.15 (1.21 dB)

Averaged over beam width

Antenna gain

9.4 dBi

9.3 dBi

Half power beam width

55°

55°

Horizontal and vertical

Radiation efficiency

81%

74%

The center frequency may shift a bit between batches as a result of variations in the dielectric constant of FR4. Also, not all brands of FR4 have the same dielectric constant. Frequency shifts up to 100 MHz are normal.

Radiation pattern

Simulated (HFSS)

Measured (anechoic chamber, averaged over full bandwidth)

Image: tfp1-rad-sim-3d-small.png

Simulated 3D radiation pattern.

Image: tfp1-rad-meas-3d-small.png

Measured 3D radiation pattern, by Antenna Test Lab.

Image: tfp1-rad-sim-2d-small.png

Simulated vertical cross-sections.

Image: tfp1-rad-meas-2d-small.png

Measured vertical cross-sections, by Antenna Test Lab.

Note: You are free to use these images for marketing purposes if you are selling Triple Feed Patch antennas as long as you link back to this page. Additionally, if you use the images based on the anechoic chamber measurements from Antenna Test Lab, please link back to antennatestlab.com as well.

VNA measurements

Image: tfp1-vna-sp-small.png

VNA measurements (S-parameters). S11 and S22 indicate the reflected power at port 1 and 2 respectively. S12 and S21 indicate how much power is leaking from one port to the other.

This gives you an idea of the kind of variations you can expect for hand-assembled antennas. I suspect that most of the variation is caused by the surface-mount SMA connectors since those were soldered by hand, and it's difficult to accurately control the amount of solder when you can't even see the center pin. This would explain why there is a lot of variation in S11 and S22, but almost no variation in S12 and S21. Based on S12 and S21 (which should be more reliable), the center frequency appears to be close to 5.7 GHz, which I suspect is a result of inaccurate spacing of the PCBs. The 4 mm spacers which I used to construct these units somehow resulted in a final spacing closer to 4.2 mm in reality.

Where can I buy one?

I have no plans to manufacture these antennas myself, I'm hoping that other antenna builders will pick up this design and start selling it.

The following manufacturers are selling the Triple Feed Patch antenna:

Manufacturer

Price* (USD)

LHCP

RHCP

Hybrid

SMA male

SMA female

RP-SMA male

RP-SMA female

Notes

Actuna

$9.85

Image: state_no.png

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Includes semi-rigid coax (SMA male – SMA male or SMA male – RP-SMA female).

FarVew

$21.99

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Image: state_yes.png

Image: state_no.png

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Includes semi-rigid coax (SMA male – SMA male or SMA male – RP-SMA female).

FlyTime

$8.78

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Image: state_yes.png

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Only ships to the Czech Republic and Slovakia.

Parkflyer

$22.5

Image: state_no.png

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Image: state_yes.png

Image: state_no.png

Image: state_yes.png

Image: state_no.png

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Includes semi-rigid coax (SMA male – SMA male).

Race412

$15

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Image: state_yes.png

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Includes semi-rigid coax.

RjxHobby

$15.29

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Includes semi-rigid coax (SMA male – SMA male).

Swiftflying

$15.28

Image: state_no.png

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Image: state_yes.png

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Includes semi-rigid coax (SMA male – SMA male).

* Based on listed price and exchange rate at time of writing. May be outdated. Shipping not included.

If you are a manufacturer who is selling this design, feel free to email me or leave a comment below.

You can also just build them yourself, it's really not that hard. Just download the design files and follow the instructions below.

License

Image: 88x31.png

This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.

This means you are free to use this design in any way you like (this includes commercial use) as long as you credit us (Maarten Baert and Robin Theunis). If you choose to modify the design files, you should share the modified design files under the same license.

Design files

Download Triple Feed Patch 1 design files (includes LHCP, RHCP and hybrid variant)

Important: This antenna will only work properly when manufactured and assembled correctly. This is not just a regular circuit board, read the instructions below!

Important: If you use Elecrow to manufacture these PCBs, you should add the following note to your order to let them know that the screw holes must be unplated:

Quote

The second PCB (pcb_tfp_1_part2_*.zip) has a separate file for non-plated-through holes (pcb_tfp_1_part2_*-npth.txt).

Parts

If you decide to build this antenna, you will need the following parts:

  • PCBs: Manufacturers will make these for you if you send them the Gerber files which are included in the design files above. I used Elecrow for my prototypes, they will make 10 PCBs for $10. That means you end up paying $2 per antenna (it gets much cheaper if you make them in larger quantities). The PCBs must use 1.0 mm thickness FR4 material, not the regular 1.6 mm thickness. The correct thickness is critical, if you get this wrong the design won't work properly at all! Regarding copper thickness, 35 µm (1 oz) is fine. Thicker copper tracks won't improve the efficiency at RF frequencies due to the skin effect. The design is tuned for standard FR4, but there may be small variations between different FR4 manufacturers which can result in a shift in the center frequency of the antenna. I specifically made sure that the design isn't too sensitive to material variations, so this shouldn't be a huge problem, but you should still avoid manufacturers that use special materials with different dielectric constants than regular FR4.

  • Copper wire: Regular copper wire with a 1.0 mm diameter is used to create the three feed pins. Tin-plated copper or similar is also fine, but don't use iron or steel wire.

  • SMA connector (vertical type): For performance reasons I used surface-mount vertical SMA connectors. I used this for my prototypes. They cost $8 for 10 pieces, so that's $1.6 per antenna. Soldering these requires a hot air rework station or reflow oven, because you can't reach the center pin with a regular soldering iron. I'm planning to make some variants with simpler edge-mount connectors that are easier to solder, but this will result in longer tracks over FR4 which means higher loss.

  • SMA connector (edge mount type): The advantage of the edge mount type is that you don't need a hot air rework station or reflow oven. This type of connector is also somewhat less likely to break. The disadvantage is that you need slightly longer PCB tracks, which results in higher loss. You can buy these connectors from many sources (example), but make sure that you get a type made for 1.0 mm PCBs, not the default 1.6 mm! Typically these connectors will have a pin spacing of 1.1 – 1.2 mm to accommodate small manufacturing variations.

Assembly

The PCBs need to be spaced accurately to get good results. The correct spacing is 4 mm. You can buy metal spacers of this height to make this easier. Ideally you need to get these distances right within a 0.1 mm tolerance.

I will add more detailed instructions when I have more time. If you're wondering how you are supposed to solder the center pin of the SMA connectors, there are two ways: pre-tin both the pad and the pin, or use solder paste (I prefer the first option). Place the connector on top of the PCB, and heat it up with a hot air rework station until they join. Adding flux helps. Use tweezers to align the connector properly if necessary. Finally use a regular soldering iron to solder the large ground pad to the connector.

Assembly jig

David Lewis (FarVew) created a nice laser-cut assembly jig which is especially useful if you want to assemble several of these antennas. It's not strictly required though, you can also assemble the antenna without this, it just takes longer.

Image: tfp1-jig-top-small.jpg

Image: tfp1-jig-side-small.jpg

Image: tfp1-jig-bot-small.jpg

Download Triple Feed Patch 1 assembly jig design files


Comments

Metrox

Comment #1: Sun, 30 Jul 2017, 0:22 (GMT+1, DST)

Quote


Just want to try to make it with my self. I am hobbyist, not a manufacturer.
I want to order PCBs at elecrow.com and have some additional questions (what I didn't found at your instruction).
They ask a lot of things what I didn't understand what this mean.
Layer: 2 layer?
PCB Thickness: It's clear - 1mm
Copper Weight: Clear also - 1oz 35um
PCB Size: What size I need to tell them? At least for price calculation they ask it. I didn't found it in your description.
PCB Color: No metter :)
Surface Finish: Hasl Lead Free?

Thank you.

Rjxhobby

Comment #2: Sun, 30 Jul 2017, 3:24 (GMT+1, DST)

Quote


it is michael from RJXHOBBY, we are manufacture, we would like to pick up this design, just to confirm, need we get authorization from you to design and sell this, thanks, your quick reply will be highly appreciated.

Best Regards,
Michael

RJX HOBBY CO., LTD
www.rjxhobby.com
skype: rjxhelis
E-mail: michael@rjxhobby.com, michael@rjxdrone.com
QQ:495828678
We chat: RJXEDNA
Tel: 0086-138 8220 5001
paypal: info@rjxhobby.com
payoneer: info@rjxhobby.com
Facebook: Michael Rjxhobby
https://www.facebook.com/rjxhobby

Maarten Baert

Administrator

Comment #3: Sun, 30 Jul 2017, 17:13 (GMT+1, DST)

Quote


Quote: Metrox

Just want to try to make it with my self. I am hobbyist, not a manufacturer.
I want to order PCBs at elecrow.com and have some additional questions (what I didn't found at your instruction).
They ask a lot of things what I didn't understand what this mean.
Layer: 2 layer?
PCB Thickness: It's clear - 1mm
Copper Weight: Clear also - 1oz 35um
PCB Size: What size I need to tell them? At least for price calculation they ask it. I didn't found it in your description.
PCB Color: No metter :)
Surface Finish: Hasl Lead Free?

Thank you.

The correct settings are:
- Layers: "2"
- PCB Thickness: "1.0mm"
- Copper Weight: "1oz 35um"
- PCB Size: "5cm Max * 5cm Max" (part1) / "10cm Max * 10cm Max" (part2)
- PCB Color: "Red" (or anything else, it really doesn't matter)
- Surface Finish: "Hasl" (or "Hasl (lead free)" if you use lead-free solder)
- PCB Stencil: "No Stencil"
- Lead time: your choice
- Panelizing: "Single PCB with milling"

Quote: Rjxhobby

it is michael from RJXHOBBY, we are manufacture, we would like to pick up this design, just to confirm, need we get authorization from you to design and sell this, thanks, your quick reply will be highly appreciated.

No authorization is required, you are free to manufacture these as long as you do what the license requires:

Quote

This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.

This means you are free to use this design in any way you like (this includes commercial use) as long as you credit us (Maarten Baert and Robin Theunis). If you choose to modify the design files, you should share the modified design files under the same license.

Metrox

Comment #4: Mon, 31 Jul 2017, 9:37 (GMT+1, DST)

Quote


Thank you for answer,
Maarten Baert

Can you tell what better wire to get (to connect Patch with goggles). Or you made it by yourself as well ?

Rjxhobby

Comment #5: Tue, 1 Aug 2017, 11:27 (GMT+1, DST)

Quote


Quote: Maarten Baert

No authorization is required, you are free to manufacture these as long as you do what the license requires:

Quote

This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.

This means you are free to use this design in any way you like (this includes commercial use) as long as you credit us (Maarten Baert and Robin Theunis). If you choose to modify the design files, you should share the modified design files under the same license.

thanks for your answer, i really appreciate it.

Best Regards,
Michael

RJX HOBBY CO., LTD
www.rjxhobby.com
skype: rjxhelis
E-mail: michael@rjxhobby.com, michael@rjxdrone.com
QQ:495828678
We chat: RJXEDNA
Tel: 0086-138 8220 5001
paypal: info@rjxhobby.com
payoneer:info@rjxhobby.com
Facebook: Michael Rjxhobby
https://www.facebook.com/rjxhobby

Last modified: Tue, 1 Aug 2017, 23:06 (GMT+1, DST)

Maarten Baert

Administrator

Comment #6: Tue, 1 Aug 2017, 23:05 (GMT+1, DST)

Quote


Quote: Metrox

Thank you for answer,
Maarten Baert

Can you tell what better wire to get (to connect Patch with goggles). Or you made it by yourself as well ?

I used the same coax as what I used for the Pagoda antenna and attached the connectors myself. It's RG402 and corresponding soldered SMA connectors. Ebay links here and here.

Race412

Comment #7: Fri, 4 Aug 2017, 0:38 (GMT+1, DST)

Quote


I'm not sure if you have a section yet for a list of retailers, or plan too. If so, I was wondering if my store could be added? We have a preorder and expect stock to be received with a week-ish.

Thank you
Race 412

https://squareup.com/store/room-412/

Fpvbrain

Comment #8: Fri, 4 Aug 2017, 12:00 (GMT+1, DST)

Quote


Hey Maarten
Here is FPV Brain from Germany
We got your antennas they get very good looking and we are just looking for 5 independent testers. The contribution we shared on Facebook is https://www.facebook.com/FPVBrain/posts/946611752143954
Our antennas are already finished but unfortunately there are difficulties with the delivery of the SMA Male RF terminal connector 50 OHM if there is a good and cheap 'address to buy would be the good

Fpvbrain

Comment #9: Sat, 5 Aug 2017, 15:27 (GMT+1, DST)

Quote


Triple Feed Patch antenna Spacer

ShareAlike

https://www.thingiverse.com/thing:2468349

Tomkanovik

Comment #10: Mon, 7 Aug 2017, 20:04 (GMT+1, DST)

Quote


Quote: Fpvbrain

Triple Feed Patch antenna Spacer

ShareAlike

https://www.thingiverse.com/thing:2468349

Maarten? Will it not affect the functionality of the antenna?

Metrox

Comment #11: Thu, 10 Aug 2017, 9:00 (GMT+1, DST)

Quote


Tomkanovik, Use it as spacer wile weld.

Zingaros

Comment #12: Thu, 10 Aug 2017, 11:07 (GMT+1, DST)

Quote


Hello Maarten, all,

Thanks again to release wonderful new gadget to the community!

Anyone interested to sell the raw PCBs by units for Europe: I m not really up for 10 pieces.

Thanks

Rjxhobby

Comment #13: Thu, 10 Aug 2017, 11:08 (GMT+1, DST)

Quote


Hi,

we have made this triple feed patch antenna already.

michael@rxjhobby.com
michael@rjxdrone.com

Zoorgaz

Comment #14: Fri, 11 Aug 2017, 13:13 (GMT+1, DST)

Quote


Hello. Awesome antenna! Do i assume correctly due to the name, I can actually use this antenna as LHCP and RHCP in 2xMiMO?

Tomkanovik

Comment #15: Fri, 11 Aug 2017, 14:02 (GMT+1, DST)

Quote


Quote: Zingaros

Hello Maarten, all,

Thanks again to release wonderful new gadget to the community!

Anyone interested to sell the raw PCBs by units for Europe: I m not really up for 10 pieces.

Thanks

A few of them i have in transit, and i am from czech republic :)

Zingaros

Comment #16: Fri, 11 Aug 2017, 15:41 (GMT+1, DST)

Quote


Quote: Rjxhobby

Hi,

we have made this triple feed patch antenna already.

michael@rxjhobby.com
michael@rjxdrone.com

Thanks Michael: I just ordered one of them. Eager to test them. I will post a short review once tested.

Maarten Baert

Administrator

Comment #17: Tue, 15 Aug 2017, 1:58 (GMT+1, DST)

Quote


Quote: Tomkanovik

Maarten? Will it not affect the functionality of the antenna?

It will definitely shift the center frequency. I don't recommend using any spacer, it's really not necessary in my experience. If you really want a spacer, use something with a very low dielectric constant and very low loss, like Styrofoam.

Quote: Zoorgaz

Hello. Awesome antenna! Do i assume correctly due to the name, I can actually use this antenna as LHCP and RHCP in 2xMiMO?

Yes, if you have a receiver with MIMO support.

Swiftflying

Comment #18: Thu, 17 Aug 2017, 5:19 (GMT+1, DST)

Quote


Dear sir

Sorry for bothering you, I just read your the article again ,
I am a manufacturer from Shanghai, China. Our company name is swiftflying and we also make antenna as you designed at the article. We are wondering if you can put our product's amazon's link into your articles, our produsct's link is
https://www.amazon.com.mx/Swiftflying-9-4dBi-Triple-Patch-antenna/dp/B074N18YYS/ref=sr_1_2?s=toys&ie=UTF8&qid=1502889480&sr=1-2&keywords=swiftflying

It would be great if you can support us. Hope we can make more cooperation in the future.

looking forward to your reply!
Sincere regards

E-mail: swiftflying@163.com
QQ:451586053
We chat: dxh1988ping
Tel: 0086-1391782 7681

Rodyparker

Comment #19: Wed, 23 Aug 2017, 3:12 (GMT+1, DST)

Quote


Hello Maarten, do you think a PCB with 0.8mm with 0.5 oz of cooper will be a problem?

Rjxhobby

Comment #20: Wed, 23 Aug 2017, 3:47 (GMT+1, DST)

Quote


Hello Maarten, all,

Thanks again to release wonderful new gadget to the community!

http://www.rjxhobby.com/rjx-rjx1647

contact michael for dealers price.

michael@rjxhobby.com or michael@rjxdrone.com

thanks again for wonderful design.

Last modified: Mon, 28 Aug 2017, 23:17 (GMT+1, DST)

Rodyparker

Comment #21: Thu, 24 Aug 2017, 0:18 (GMT+1, DST)

Quote


other question, the top pcb has to be 2 layers also?

Tomkanovik

Comment #22: Fri, 25 Aug 2017, 10:52 (GMT+1, DST)

Quote


Hello i add this antenna to my store. here is link http://flytime.cz/product/TRIPLEFEEDPATCH. And i add LHCP pagoda to my Flytime store. :)

Maarten Baert

Administrator

Comment #23: Mon, 28 Aug 2017, 23:18 (GMT+1, DST)

Quote


Quote: Rodyparker

Hello Maarten, do you think a PCB with 0.8mm with 0.5 oz of cooper will be a problem?

Yes. This design is made for 1mm FR4 and will not work properly with anything else.

Quote: Rodyparker

other question, the top pcb has to be 2 layers also?

Not strictly required, but for physical strength it helps a lot to have solder pads on both sides.

Rjxhobby

Comment #24: Tue, 29 Aug 2017, 4:24 (GMT+1, DST)

Quote


we have designed these antenna, you can see my facebook:

https://www.facebook.com/rjxhobbyedna

or contact my email for special price: edna@rjxdrone.com

Dave855

Comment #25: Tue, 29 Aug 2017, 8:33 (GMT+1, DST)

Quote


Thanks again Maarten!

Far Vew finally got their version up and on!
They include an extension with either SMA or RP-SMA and also include a 50ohm dummy load.

https://farvew.com/home/69-triple-feed-patch-lhcp-and-rhcp.html

Thanks Maarten you and Robin have reshaped FPV again!

Rodyparker

Comment #26: Sat, 2 Sep 2017, 18:28 (GMT+1, DST)

Quote


Quote: Maarten Baert
Quote: Rodyparker

Hello Maarten, do you think a PCB with 0.8mm with 0.5 oz of cooper will be a problem?

Yes. This design is made for 1mm FR4 and will not work properly with anything else.

Quote: Rodyparker

other question, the top pcb has to be 2 layers also?

Not strictly required, but for physical strength it helps a lot to have solder pads on both sides.

Thank you very musch for the answer, I'm doing a prototype in home with the right board and I also ask to elecrow some pieces.

Erwin024

Comment #27: Sat, 9 Sep 2017, 6:17 (GMT+1, DST)

Quote


Hi, when using triple feed patch antenna, do I still have to use diversity module?
Or if I'll use diversity module, which can I pair with triple feed patch antenna?
Thanks

Rjxhobby

Comment #28: Sat, 9 Sep 2017, 7:30 (GMT+1, DST)

Quote


we have this Triple Feed Patch antenna

https://www.facebook.com/rjxhobby

michael@rjxhobby.com

Feket663

Comment #29: Sat, 16 Sep 2017, 19:58 (GMT+1, DST)

Quote


Hi! I'd like buy this great designed antenna. But have a question: can I use a cheap 50 ohm SMA dummy load from ebay or aliexpress. My biggest problem is this dummy loads specified only 3 GHz.

For example: link

Can I use it?

Last modified: Mon, 23 Oct 2017, 1:17 (GMT+1, DST)

Flick1

Comment #30: Wed, 20 Sep 2017, 9:24 (GMT+1, DST)

Quote


Hi Maarten,
When you mention using the surface mount SMC connectors for performance reasons, what kind of performance degradation would you expect if you used the PCB mount connectors with longer legs?

Gs550t1981

Comment #31: Tue, 3 Oct 2017, 4:52 (GMT+1, DST)

Quote


I'm not to good at understanding the graphs. What is the radiation pattern? When pointing the antenna straight ahead is it basically 55° verticle and horizontal? What makes them better than say a crosshair? I am asking not to bust your chops. I love the Pagodas and are the only antenna I use. I picked this up and want to know what it would be ideal to use for... Thanks
Jeff

Fpvbrain

Comment #32: Sun, 15 Oct 2017, 3:08 (GMT+1, DST)

Quote


It will definitely shift the center frequency LOL since when determined PLA or ABS the center frequency Maarten Baert I would like gladly times a field strength test of ABS or PLA from you see which you can send me gladly to info@FPV-BRAIN.net then you may not synonymous PCB More paint. :-)

Fpvbrain

Comment #33: Sun, 15 Oct 2017, 3:21 (GMT+1, DST)

Quote


Conductivity of insulators κ in S / cm rubber10-16 polystyrene 10-18 porcelain 10-15

Akinys

Comment #34: Sat, 21 Oct 2017, 20:19 (GMT+1, DST)

Quote


If to use only RHCP, what option will be best:
- do not solder SMA connector on LHCP side;
- solder SMA connector on LHCP side and leave open;
- solder SMA connector on LHCP side and put 50ohm load;
- remove from pcb feeder line from LHCP side ?

Maarten Baert

Administrator

Comment #35: Sun, 29 Oct 2017, 2:05 (GMT+1, DST)

Quote


Quote: Erwin024

Hi, when using triple feed patch antenna, do I still have to use diversity module?
Or if I'll use diversity module, which can I pair with triple feed patch antenna?
Thanks

Typically directional antennas like these are combined with an omnidirectional antenna (like the Pagoda) in a diversity setup. You can use them without diversity if you want, but then you need to make sure that you are always pointing the antenna in the right direction.

Any diversity module should work with any antenna, as long as the connectors are compatible.

Quote: Feket663

Hi! I'd like buy this great designed antenna. But have a question: can I use a cheap 50 ohm SMA dummy load from ebay or aliexpress. My biggest problem is this dummy loads specified only 3 GHz.

For example: link

Can I use it?

Any 50 ohm terminator should work, it's not critical. You can even use the antenna without a terminator, it will still work fine, the axial ratio will just be slightly worse because the opposite polarization will be reflected instead of absorbed.

Quote: Flick1

Hi Maarten,
When you mention using the surface mount SMC connectors for performance reasons, what kind of performance degradation would you expect if you used the PCB mount connectors with longer legs?

The problem is that the through-hole connectors would need a hole in the ground plane, which interferes with the patch antenna on the other side. It's also really difficult to get a good 50 ohm match with those connectors at high frequencies.

Quote: Gs550t1981

I'm not to good at understanding the graphs. What is the radiation pattern? When pointing the antenna straight ahead is it basically 55° verticle and horizontal? What makes them better than say a crosshair? I am asking not to bust your chops. I love the Pagodas and are the only antenna I use. I picked this up and want to know what it would be ideal to use for... Thanks
Jeff

If you point the patch straight at the other antenna, that's considered 0 degrees (the top of the radiation pattern graph).

These aren't necessarily better than crosshairs, but they are easier to manufacture because they aren't as sensitive to deviations in length of the radiating elements. Also, this antenna achieves a good axial ratio across the entire bandwidth, whereas crosshairs typically only get a good axial ratio close to their center frequency. Finally, this antenna has a good axial ratio in all directions, not just when it is pointed straight at the other antenna but also at an angle. This is rarely the case for rectangular patches or crosshair antennas.

Quote: Fpvbrain

It will definitely shift the center frequency LOL since when determined PLA or ABS the center frequency Maarten Baert I would like gladly times a field strength test of ABS or PLA from you see which you can send me gladly to info@FPV-BRAIN.net then you may not synonymous PCB More paint. :-)

Quote: Fpvbrain

Conductivity of insulators κ in S / cm rubber10-16 polystyrene 10-18 porcelain 10-15

... what?

Conductivity is irrelevant in this context, what matters is dielectric constant and loss tangent. The dielectric constant of air is 1.0, for plastic it is usually somewhere between 2.0 and 3.0 depending on the type and density. The resonance frequency of a patch is inversely proportional to the square root of the dielectric constant. This is basic antenna theory which you can find in any book that discusses patch antennas.

For example, if you used a polyethylene spacer (dielectric constant 2.26), you will shift the resonant frequency from 5.8 GHz down to 3.86 GHz. Of course the feed network isn't affected by this since it is on the other side of the PCB. So you now have an antenna with a 5.8 GHz feed network and a 3.86 GHz patch, so your antenna will be pretty much useless.

The Pagoda was less susceptible to this because the space between the plates contains only a small part of the electromagnetic fields. As a result you could put a spacer between the two and still get an antenna that was usable. This is not the case for patch antennas, where 99% of the electromagnetic field is concentrated between the two plates.

Quote: Akinys

If to use only RHCP, what option will be best:
- do not solder SMA connector on LHCP side;
- solder SMA connector on LHCP side and leave open;
- solder SMA connector on LHCP side and put 50ohm load;
- remove from pcb feeder line from LHCP side ?

Option 3, but if you don't want to add the SMA connector, you could also solder a 50 ohm SMD resistor directly to the PCB. Removing the connector is also possible, but don't remove the feed line. The feed network in the center has been designed with the feed line taken into account, removing it will affect the performance.

An even better option is to use an alternative feeding network that is LHCP or RHCP only, but I haven't made that one public yet because I didn't have time.

Ryan

Comment #36: Tue, 31 Oct 2017, 14:29 (GMT+1, DST)

Quote


What is center frequency? I run my vtx on channel 5658. Am I off center? Is center as close to 5800 as possible? Does it matter how the patch sits on the goggles ? Is there a up or down/top or bottom of the patch?

Last modified: Wed, 1 Nov 2017, 23:12 (GMT+1, DST)

Vlado

Comment #37: Thu, 2 Nov 2017, 20:25 (GMT+1, DST)

Quote


Would it work well if I solder RG402 cable directly to the PCB? How about soldering rx5808 video rx module on the antenna? :D

Maarten Baert

Administrator

Comment #38: Sat, 4 Nov 2017, 3:43 (GMT+1, DST)

Quote


Quote: Ryan

What is center frequency? I run my vtx on channel 5658. Am I off center? Is center as close to 5800 as possible? Does it matter how the patch sits on the goggles ? Is there a up or down/top or bottom of the patch?

The center frequency is 5.8 GHz. As you can see in the specs, the bandwidth is 660 MHz (5.47 – 6.13 GHz), so 5.658 GHz will work fine.

There is no top/bottom, just point the patch in the direction of the transmitter and you are fine.

Quote: Vlado

Would it work well if I solder RG402 cable directly to the PCB? How about soldering rx5808 video rx module on the antenna? :D

That won't work well with the current PCB layout. The matching will be bad. The layout you see now is specifically tuned to match well to those vertical SMA connectors.

Andymidtf

Comment #39: Thu, 16 Nov 2017, 20:41 (GMT+1, DST)

Quote


Quote: Maarten Baert

The correct settings are:

- PCB Size: "5cm Max * 5cm Max" (part1) / "10cm Max * 10cm Max" (part2)
...
- Panelizing: "Single PCB with milling"

Hi Maarten,

I am ordering from Seeed, there the PCB size can be much smaller - from the .dxf files I see part one is 24.9mm wide, and part 2 is 60.0mm wide - any reason not to use these sizes in the order page?
Also, neither Elecrow or Seeed provide the Panalizing option in the web form - any idea what will happen if this is not included in the order? I should get in contact with them for a personal quote?

Thanks very much!

Andy
:-)

PD do you have a paypal or accept bitcoin (better some other vcoin with todays tx rates!), even thou you offer these open source, I really think you deserve some renumeration for your excellent work!

Actuna

Comment #40: Sun, 26 Nov 2017, 22:03 (GMT+1, DST)

Quote


Hello ...

I would like to inform you about the production and sale of the Triple Feed Patch (hybrid):

Manufacturer: ACTUNA

URL: https://actuna.com/Antenna-Triple-Feed-Patch-1-5-8GHz-RHCP-LHCP-p13210

Price: 9,85 $

- hybrid
- SMA (female)
- SMA and RP-SMA - Includes semi-rigid coax (SMA male – SMA male or SMA male - RP-SMA female).

Notes: Each antenna is measured individually and gets its own parameters tab. SMA and RP-SMA - Includes semi-rigid coax (SMA male – SMA male or SMA male - RP-SMA female). Fast delivery in the EU (3-10 days).

Contacts: actuna@actuna.pl

PS:

We produced a modified version of the Triple Feed Patch (hybrid) antenna - a diameter of 45mm. We are now finishing the tests of this antenna, the results are positive.

Last modified: Sun, 26 Nov 2017, 22:05 (GMT+1, DST)

Prxbl

Comment #41: Mon, 27 Nov 2017, 13:06 (GMT+1, DST)

Quote


Since male SMA terminators are hard to find can I use a 49.9ohm resistor to terminate one of the sides permanently?

I plan to remove the SMA connector and just solder an SMD resistor between signal and ground in the place of the old connector.

Maarten Baert

Administrator

Comment #42: Wed, 29 Nov 2017, 3:34 (GMT+1, DST)

Quote


Quote: Andymidtf

Hi Maarten,

I am ordering from Seeed, there the PCB size can be much smaller - from the .dxf files I see part one is 24.9mm wide, and part 2 is 60.0mm wide - any reason not to use these sizes in the order page?
Also, neither Elecrow or Seeed provide the Panalizing option in the web form - any idea what will happen if this is not included in the order? I should get in contact with them for a personal quote?

Thanks very much!

Andy
:-)

PD do you have a paypal or accept bitcoin (better some other vcoin with todays tx rates!), even thou you offer these open source, I really think you deserve some renumeration for your excellent work!

If the manufacturer asks for the exact size, then you should do that. Elecrow doesn't do this though. If they don't offer panelization, then don't worry about it. Also, I don't accept donations, but thanks anyway :).

Quote: Prxbl

Since male SMA terminators are hard to find can I use a 49.9ohm resistor to terminate one of the sides permanently?

I plan to remove the SMA connector and just solder an SMD resistor between signal and ground in the place of the old connector.

You should just get the LHCP or RHCP variant instead of the hybrid if that is what you want. But yes, you can do this. It won't be perfect because the footprint is designed to cancel out some of the mismatch of the connector, but it will be pretty close.

Last modified: Wed, 29 Nov 2017, 3:37 (GMT+1, DST)

Actuna

Comment #43: Fri, 1 Dec 2017, 15:12 (GMT+1, DST)

Quote


Quote: Actuna

We produced a modified version of the Triple Feed Patch (hybrid) antenna - a diameter of 45mm. We are now finishing the tests of this antenna, the results are positive.

https://www.thingiverse.com/thing:2682348

Race412

Comment #44: Tue, 5 Dec 2017, 19:26 (GMT+1, DST)

Quote


Hello Maarten,
We also have the triple feed patch antenna available on our store. Could you add our store to the table as well?

https://race412.com/product/triple-feed-patch/
$15
SMA and RPSMA

Thank You
Race 412

Maarten Baert

Administrator

Comment #45: Wed, 6 Dec 2017, 1:10 (GMT+1, DST)

Quote


Quote: Race412

Hello Maarten,
We also have the triple feed patch antenna available on our store. Could you add our store to the table as well?

https://race412.com/product/triple-feed-patch/
$15
SMA and RPSMA

Thank You
Race 412

Can you specify which connectors you are using on the PCB as well as the coax? Is the PCB connector also RP-SMA or just one of the connectors on the coax?

Race412

Comment #46: Sat, 6 Jan 2018, 1:50 (GMT+1, DST)

Quote


Quote: Maarten Baert
Quote: Race412

Hello Maarten,
We also have the triple feed patch antenna available on our store. Could you add our store to the table as well?

https://race412.com/product/triple-feed-patch/
$15
SMA and RPSMA

Thank You
Race 412

Can you specify which connectors you are using on the PCB as well as the coax? Is the PCB connector also RP-SMA or just one of the connectors on the coax?

Yes, sorry for the long response time, we make the plate exactly the way you do for the connectors, but the coax can be made for either an SMA or RPSMA receiver.

Edit: typo

Last modified: Sat, 6 Jan 2018, 1:51 (GMT+1, DST)

Timkostka

Comment #47: Sun, 4 Feb 2018, 18:33 (GMT+1, DST)

Quote


Can I remove the 4 holes on this without affecting the performance?

Any guesses on how the performance would change if I made the bottom PCB 57.5mm in diameter instead of 60mm? (to fit 2 into a 10x10cm panel)

Last modified: Sun, 4 Feb 2018, 22:15 (GMT+1, DST)

Maarten Baert

Administrator

Comment #48: Tue, 13 Feb 2018, 1:29 (GMT+1, DST)

Quote


Quote: Timkostka

Can I remove the 4 holes on this without affecting the performance?

Any guesses on how the performance would change if I made the bottom PCB 57.5mm in diameter instead of 60mm? (to fit 2 into a 10x10cm panel)

The mounting holes have no impact on performance. Changing the diameter has a small effect on the directivity, but 2.5mm won't make a significant difference.

Goatzilla

Comment #49: Thu, 15 Mar 2018, 4:30 (GMT+1, DST)

Quote


On the antenna it says, "Keep this area clear".

What exactly does that mean?

For my setup it's easiest if I use a right angle adapter and send the cable out the side. Is that going to cause problems?

Maarten Baert

Administrator

Comment #50: Sun, 25 Mar 2018, 1:21 (GMT+1, DST)

Quote


Quote: Goatzilla

On the antenna it says, "Keep this area clear".

What exactly does that mean?

For my setup it's easiest if I use a right angle adapter and send the cable out the side. Is that going to cause problems?

No, as long as you keep the cable and connector at least 1 cm away from the tracks it's not going to have an impact.

Xaled

Comment #51: Sun, 1 Apr 2018, 20:56 (GMT+1, DST)

Quote


Hi Maarten,
I was curious if you had any success with 2,45 Ghz design?
The CubeSat communication in S-band 1.98-2.02 GHz and 2.17-2.2 GHz would greatly benefit from an affordable antenna design.

Maarten Baert

Administrator

Comment #52: Sun, 15 Apr 2018, 14:26 (GMT+1, DST)

Quote


Quote: Xaled

Hi Maarten,
I was curious if you had any success with 2,45 Ghz design?
The CubeSat communication in S-band 1.98-2.02 GHz and 2.17-2.2 GHz would greatly benefit from an affordable antenna design.

I don't have enough time to redesign this antenna for all possible frequencies. But it shouldn't be too hard to do this yourself, especially if you use the simpler one-port feed network instead of the hybrid LHCP/RHCP version.

Prouser27

Comment #53: Wed, 30 May 2018, 14:48 (GMT+1, DST)

Quote


Hello Maarten!

On the vertical cross-section image it looks like as the LHCP is more "stronger" as the RHCP polarization? The LHCP polarization looks like an big signal bubble in on direction and the RHCP much smaller.

Or are the two polarizations equally strong?

Last modified: Wed, 30 May 2018, 14:50 (GMT+1, DST)

Maarten Baert

Administrator

Comment #54: Fri, 1 Jun 2018, 1:43 (GMT+1, DST)

Quote


Quote: Prouser27

Hello Maarten!

On the vertical cross-section image it looks like as the LHCP is more "stronger" as the RHCP polarization? The LHCP polarization looks like an big signal bubble in on direction and the RHCP much smaller.

Or are the two polarizations equally strong?

The images show the radiation pattern when a signal is applied to the LHCP port and the RHCP port has only a 50 ohm terminator connected to it. It's not supposed to transmit any RHCP radiation. If you swap the signal to the other port, LHCP and RHCP will be swapped as well. So LHCP and RHCP are equally strong, at least when using the right port.

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