X-Band 130-nm CMOS transceiver front-end with a broadband attenuator design for phased-array systems

This letter demonstrates an X-band transceiver front-end in 130-nm CMOS technology for phased-array systems. To solve the problem that passive attenuator performance deteriorates significantly in wideband systems, a 6-bit attenuator with source follower and common-gate amplifier is proposed. Besides, an 8-bit vector-summing phase shifter is implemented in common path to realize the phase coverage of 360 degrees with the least significant bit of 5.625 degrees. In the frequency range of 8-12 GHz, the measured root-mean-square (rms) amplitude and phase errors of the attenuator in the transceiver are less than 0.36 dB and 2.2 degrees, respectively. The rms phase and amplitude errors of the phase shifter in the transceiver are less than 4.8 degrees and 0.56 dB, respectively. The whole chip area including pads is 3 x 2.3 mm2.