What is involved in making a broadband "90 degree hybrid"

[cdev]

I would like to make a 90 degree hybrid so I can make four arm antennas and have them work properly.

I have no idea of how to go about doing this. Some other four arm antennas do include structures that do this but I dont understand them. Alternatively, are there any cheap broadband 90 degree hybrids available for SMD that cost under 10 each and are available in smaller quantities? (less than 10 at a time)

This would be for approximately 1.1 to perhaps 1.7 or ideally slightly more than 2.2 gHz  Main usage would be fooling around, basically antenna experimentation using GPS and satellites as the test signals.

I should say here that for single frequency antennas, at lower frequencies, one can use a quarter wavelength stub made with higher impedance coax to get a 90 degree phase shift.. so its likely something similar could be done with microstrip for a single frequency antenna.

[hendorog]

There are some SMD couplers on ebay, likely not quite an exact match for your frequency range.

Search for 'Hybrid Coupler'

[KJDS]

Look at Anaren's Xinger range of couplers

IPP do similar things and Mini-circuits may have something too.

[Kire Pûdsje]

If you want microstrip. try branch line couplers.
For 50 ohm, you might need a double section version to reach the bandwidth.
If you have the opportunity to make the antenne impedance 100 ohm, BLC's could give you very wideband perfomance.

[cdev]

Kire,

***Thank you***

Indeed, "Branch line coupler" was the term I needed to know..


  Also, this will work handily... especially for single band antennas..

This will likely work well for "single band" (GPS L1 + Glonass + Beidou + QRSS) antennas.

100 ohms is likely a better match to most of the experimental antennas I fool around with than 50 ohms.

 

[Kire Pûdsje]

If your manufacturing process has the accuracy, you might also want to have a look at Lange couplers.
In a PCB process you can replace the bondwires/bridges by 0 ohm resistors.