Circularly polarized 20-GHz high-temperature superconducting microstrip antenna array

A four-element array of circularly polarized 20-GHz YBa/sub 2/Cu/sub 3/O/sub x/ microstrip antennas has been fabricated on LaAlO/sub 3/ and characterized. The array produced good circular polarization, and the gain of the array at 77 K, relative to a copper array of the same design at 77 K, was approximately 0.75 and 1.3 dB for the two gain measurement methods presented. The relative gain increased to approximately 2.2 dB at 30 K. The results demonstrate that high-temperature superconductors, when used in microstrip antenna arrays, improve the efficiency of the array, and that circularly polarized microstrip arrays can be fabricated on LaAlO/sub 3/.