C-band 6-bit GaAs monolithic phase shifter

Design, fabrication, and performance of a 6-bit GaAs monolithic phase shifter for use in the 5-6-GHz frequency range are described. The chip includes an analog control bit (0-11°) for phase correction in a closed-loop configuration and five digitally controlled phase bits. A ± 1° phase variation was achieved for the 11.25°, 22.5°, and 45° bits while for the 90° and 180° bits the phase variation was ±6° over 5 to 6 GHz. The return loss was better than 15 dB and insertion-loss flatness was within ± 1 dB over this frequency band. The phase error over a temperature range of 25-80°C and the 5-6-GHz frequency band was less than ± 0.5°, ± 1°, ± 1°, ± 2°, and ± 2° for the 11.25°, 22.5°, 45°, 90°, and 180° bits, respectively, with a maximum of .8-dB insertion-loss variation.