Secure Satellite Communication Digital IF CMOS $Q$ -Band Transmitter and $K$ -Band Receiver

Abstract

This paper reports the first CMOS RF integrated chipset for secure commercial and military satellite communication enabling next-generation low size, weight, and power (SWaP) terminals. This chipset is a significant departure from current terminals relying on individually qualified IC components by taking advantage of advanced CMOS integration. The transmitter and receiver designs are digital IF architectures that rely on the higher sampling rate capability of CMOS, and precise digital filtering, quadrature frequency translation, and frequency hopping/de-hopping. The CMOS transmitter is a fully integrated system-on-chip (SoC) design, while the receiver consists of a co-designed RF and digital IF receiver. The Tx/Rx uses a 200-/300-MHz double data rate (DDR) interface driving/receiving a complex frequency translator with sub-hertz frequency hopping resolution via on-chip numerically controlled oscillators (NCO). The transmitter includes two 12-b return-to-zero (RZ) digital-to-analog converters (DACs) and quadrature modulator to form a single-sideband (SSB) upconverter achieving >30-dB spur rejection. An RF upconverter with an X2 multiplier drives a 24-dBm $Q$ -band CMOS stacked power amplifier (PA). The RF receiver implements a matched inverter amplifier (IA) followed by a complementary active balun that current drives a passive mixer with a trans-impedance active combiner. The digital IF receiver includes a high-linearity variable gain amplifier (VGA) that drives an 8 $\times $ time-interleaved 1.2-GS/s analog-to-digital converter (ADC) with dc offset and gain calibration with an embedded digital receiver. Both the transmitter and receiver use a 1.5-GHz IF signal. The combined CMOS chipset was demonstrated with a current military satcom modulation and protocol and achieves 5 $\times $ lower power consumption and size versus the current configuration.