A 71-to-76GHz 8-Element Switchless Isolated Spectrum Phased-Array Transceiver with Direct-Modulation and Reflectionless Sliding-IF

In this paper, a 71–76GHz 8-element switchless isolated spectrum phased-array transceiver (TRX) using the direct-modulation and reflectionless sliding-IF is proposed. The quadrature direct-modulation transmitter (TX) and reflectionless sliding-IF heterodyne receiver (RX) are developed to achieve the proposed TX/RX isolation without extra isolation elements or switching operations. The 2×8-bit quadrature direct-modulator is used to generate the high-data rates modulation signals. To suppress the intermodulation and high-order mixing products, the signal absorption network is adopted in RX architecture to reject the out-of-band signal reflected back to mixer. The proposed 8-element TRX is implemented in a conventional 40-nm CMOS technology. The fabricated phased-array TRX features 16.7–17.3dBm TX output power and 6.3–6.7dB RX noise figure within 71–76GHz. Meanwhile, it shows typical 45.9dBc isolation for TX and 52.1dBc rejection for RX. The proposed 8-element TRX array steers a ±30° beam range and supports modulation signals for 4.8Gb/s 16-QAM and 3Gb/s 64-QAM.