A Monolithic Dual-Band 77/94 GHz Transceiver Front-End With Shared Frequency Multiplier

Liang Chen,Yan Wang,Lei Zhang

doi:10.1109/access.2019.2958339

Abstract

This paper presents a monolithic dual-band 77/94 GHz transceiver front-end with shared frequency multiplier. The transceiver front-end consists of two transmitters and receivers, operating at 77 GHz and 94 GHz respectively to support dual-band operation. In order to reduce the dc power consumption and save chip area, a shared frequency multiplier between the two bands is adopted in this work. We employ a frequency tripler cascaded with a doubler as the frequency multiplier to generate the desired 77 GHz signal and to lower down the frequency and phase noise of the local-oscillator (LO). The 94 GHz signal is produced by the generated 77 GHz signal up-mixing with the LO input to share the frequency multiplier for low power and low cost. The conversion gain of the multiplier is boosted by the efficiency enhancement technique in frequency tripler and the proposed gain boosting unit in the output power buffer. Besides, a frequency shunt network at the mixer output is utilized to short the unwanted mixed signal and improve the linearity of the 94 GHz transmitter. The measured saturated output power ${{P_{sat}}}$ and 3-dB bandwidth of the 77/94 GHz band transmitter are 14.2/12.35 dBm and 7.5/6 GHz, respectively. A 37.05/27.7 dB receiver conversion gain, 8.8/14.8 dB double side band noise figure are measured in the 77/94 GHz band receiver. The transceiver occupies a core area of 1.12 mm $\times2.46$ mm and draws 450 mA from a 1.2 V supply voltage.

Highlights

The low cost standard CMOS process instead of compound semiconductor or Si-Ge BiCMOS process has allowed the rapid development of high integration millimeter-wave applications such as the emerging automotive and imaging radars (77/94 GHz) [1], [2]
The simplified schematic of the amplifier with transformers for input, inter-stage and output matching is shown in Fig. 5 (a) and the transformer model with source, transformer and load impedance is provided in Fig. 5 (b), in which the source and load impedance of MOS transistor are modelled as R and C in parallel in order to simplify the transformer based matching network analysis
The measured and simulated conversion gain and output power of 77 GHz transmitter versus frequency range is depicted in Fig. 16 (a) and (b), where a maximum measured 23.9 dB power gain and 14.29 dBm output power are achieved and the output power variation is less than 2 dBm from the desired 76 GHz to 81 GHz band

Summary

INTRODUCTION

The low cost standard CMOS process instead of compound semiconductor or Si-Ge BiCMOS process has allowed the rapid development of high integration millimeter-wave applications such as the emerging automotive and imaging radars (77/94 GHz) [1], [2]. The transceiver achieves a 35/31 dB receiver gain, 4.5/8 dB double side-band noise figure and 14.5/10.5 dBm transmitter power in the 24/79 GHz bands. We propose a monolithic dual-band 77/94 GHz transceiver front-end with a shared frequency multiplier as the LO path for automotive and imaging radar application. The proposed transceiver front-end architecture can achieve dual-band generation with only one frequency synthesizer and a shared frequency multiplier. The transceiver incorporates two receivers, two transmitters and a shared wide-band frequency multiplier to support the dualband operation and lower down the frequency and phase noise of the FMCW signal generator. Two common-source pseudo-differential power amplifiers (PAs) with transformer based wide-band matching network, operating at 77 GHz and 94 GHz respectively, are adopted in the transmitter to ensure the dual-band signal can be transmitted simultaneously. A larger than 8.5 dBm output power is required for the 94 GHz band under 20 meter detection distance

TRANSMITTER

RECEIVER

CONCLUSION