A C-Band MMIC Multi-Functional Core Chip with 7 Bits Phase Shifter and Attenuator Using GaAs pHEMT

This paper demonstrates about MMIC multi-function core chip with the operating frequency range from 5GHz to 6G Hz for space payload earth observation applications. The core chip has been realized using 0.15um GaAs pHEMT process to design 7-bits phase shifter, 7-bits attenuator, three amplifiers, and -bits parallel to serial converter. The attenuator possesses an attenuation of 31.5dB with O.25dB step. The proposed 7-bits phase shifter depicts low insertion loss of 9.5dB, good return loss of less than -10dB and lower amplitude variation of 0.5dB in between the 128-phase states. This work conveyed the deep physical insight for phase shifter and attenuator is that they must be designed by taking into account the EM coupling effects of adjoining components. The core chip signifies the RMS phase and attenuator error of less than 6° and 0.5dB respectively in the desired frequency band. The two realized functionalities has the dimension of 3.8mm * 1.lmm including RF and DC pads.