I had been inspired to try ATV (amateur TV) on 23-cm and built this antenna to feed an old 10-foot C-band satellite dish I had.
The design is based on plans for a WiFi biquad that I found on the Internet: Biquad Antenna Construction
I scaled these dimensions for my frequency and made adjustments along the way.
I first bent a length of 12-guage solid copper wire (common house wire), a total of 19.5 inches, into a shape to make two squares with the ends at the center of the long dimension.
Then I made a reflection plane with an additional 1/2-inch on each side to help the directivity (the lips).
I fed the antenna with some semi-ridged scrap coax and adjusted the offset from the reflection plane for lowest SWR (about 1/4-wave away).
I’ve added an SMA connector to fit with my 23-cm ATV station.
Below is an SWR plot I made with an antenna analyzer. The SWR shown is a bit off as the station it is used with is a 75-ohm station and the analyzer is 50-ohm. It works well nonetheless.
I also made gain measurements comparing to a reference dipole antenna from a distance of 30 feet and measured a 9.9 dBd gain at operating frequency. This comparison worked well given the flat dipole's nominal impedance of 72-ohms.
I’ve been most pleased with this design and have even made a DTV antenna that works just as well as commercial antennas. I would suggest one for directed 70-cm operations over many of the popular yagi style antennas, as I believe they have a better F/B ratio.