Analysis and Design of a Broadband Receiver Front End for 0.1-to-40-GHz Application

In this paper, a broadband receiver front end for 0.1 to 40 GHz application, fabricated using 0.15-mu m GaAs E-mode pHEMT process, is reported. The receiver front end consists of a broadband low-noise amplifier (LNA) and a broadband mixer. To achieve low noise and significant bandwidth extension, a three-stage LNA, cascading one stage cascode amplifier with feedback and bandwidth extension techniques, to two stage cascode Darlington amplifiers with feedback, is proposed. The bandwidth extension principles of LNA are analyzed theoretically and verified experimentally. Measurement results show that the proposed LNA exhibits an average gain of 23.7 dB with +/- 1.5-dB variation, a typical noise figure of 3.8 dB, maximum OP1dB of 8.7 dBm in the frequency range from 0.1 to 40 GHz. A symmetric distributed drain mixer (SDDM) is proposed to provide broad bandwidth while ensuring an IP1dB of up to 5.8 dBm. The design procedure of SDDM is presented in detail. Experimental results indicate that the SDDM features a less than 7-dB conversion loss, an IP1dB of up to 5.8 dBm with zero dc dissipation and better than 15-dB isolation of LO-to-RF and IF-to-RF ports from 0.1 to 40 GHz. Finally, the LNA and SDDM are integrated as a 0.1 to 40-GHz receiver front end. Measurements illustrate that the receiver front end shows good matching with better than 10-dB return loss at RF and LO ports, and larger than 15-dB conversion gain in 0.1 to 40-GHz frequency range. The receiver occupies only 1.89-mm(2) chip area including test pads. To the best of the authors' knowledge, the designed receiver front end has the widest bandwidth among reported receivers fabricated by using GaAs process.