A High-Efficiency 27-30-GHz 130-nm Bi-CMOS Transmitter Front End for SATCOM Phased Arrays

A high-efficiency 27-30 GHz 0.13-mu m BiCMOS transmitter front end for mobile satellite communication (SATCOM) phased arrays is presented. A system-level analysis for determining the key parameters of the RF front end for the case of a SATCOM user terminal for geostationary Earth orbit (GEO) is presented. The building blocks of the beamformer, consisting of a phase shifter, variable attenuator, and power amplifier, are fully characterized. A 360 degrees phase shifter with an accuracy of 7 bits and amplitude error of +/- 1.5 dB is integrated with a variable attenuator that provides a gain variation of 16 dB with phase error of +/- 5 degrees. The chip has a measured transducer gain of 23 dB and a power consumption of 45 mW at OP1dB of 10.8 dBm. The power-added efficiency (PAE) of 26.7% is measured for the entire channel at OP1dB. An error vector magnitude (EVM) of -28 dB at P-out,P- avg of 6 dBm and PAE(avg) of 12% is measured for a 400-MHz bandwidth 64-QAM modulated signal. The overall size of the chip is 1.18 x 2.23 mm(2).