Broadband 400-GHz InGaAs mHEMT Transmitter and Receiver S-MMICs

Abstract

The modeling, design, and experimental evaluation of both a 400-GHz transmitter and receiver submillimeter-wave monolithic integrated circuit (S-MMIC) is presented in this article. These S-MMICs are intended for a radar-based system in the aforementioned operating frequency. The transmitter occupies a total chip area of $750\times 2750\,{\mu {\rm m}^2}$. It consists of a multiplier-by-four, generating the fourth-harmonic of the WR-10 input signal, which drives the integrated WR-2.2 power amplifier. The latter has an output-gate width of 128 $\mu$m. The receiver S-MMIC, $750\times 2750\,{\mu {\rm m}^2}$, consists of a multiplier-by-two, providing the second harmonic of the WR-10 input signal for the local-oscillator port of the subsequent integrated subharmonic mixer. The radio-frequency port of the latter, connects via a Lange coupler to a WR-2.2 low-noise amplifier (LNA). All the components included, are processed on a 35-nm ${\text{InAlAs}}/{\text{InGaAs}}$ metamorphic high-electron-mobility transistor integrated-circuit technology, utilizing two-finger transistors and thin-film microstrip lines (TFMSLs). The modeling approach of the amplifier cores and the respective design decisions taken are listed and elaborated-on in this work. Accompanying measurements and simulations of the transmitter and receiver are presented. The individual components of the aforementioned S-MMICs, are characterized and the results are included in this article. The state-of-the-art, for S-MMIC based circuits operating in the WR-2.2 band, is set by the LNA, on one side, spanning an operational 3-dB bandwidth (BW) of 310 to 475 GHz, with a peak gain of 23 dB and, on the other side, by the final transmitter design, which covers an operating range of 335 to 425 GHz with a peak-output power of 9.0 dBm and accompanying transducer gain of 11 dB. The included transmitter- and receiver-designs represent a first-time implementation in the mentioned technological process, utilizing solely TFMSLs, boasting the integration level, operating in the WR-2.2 frequency band, and setting the state of the art - to the authors' best knowledge - for all S-MMIC based solutions in the respective frequency band, in terms of output power and gain over the operating 3-dB BW.