Low conversion-loss fourth subharmonic mixers incorporating cmrc for millimeter-wave applications

TLDR

The paper proposes low‑conversion‑loss millimeter‑wave fourth subharmonic mixer designs. The authors design a 35‑GHz fourth‑subharmonic mixer with four open/shorted stubs, then improve it by replacing two shunt stubs with a dual‑frequency in‑line stub built from compact microstrip resonating cells (CMRCs). The improved mixer achieves a conversion loss as low as 6.1 dB at 35 GHz with a 6‑GHz 3‑dB bandwidth, remains below 16 dB across the Ka band, and offers a low‑cost, high‑performance solution for RF subsystems.

Abstract

Low conversion-loss millimeter-wave fourth subharmonic (SH) mixer designs are proposed in this paper. A millimeter-wave (35 GHz) fourth SH mixer with four open/shorted stubs is designed and measured. The conversion loss is less than 15 dB within a 2.4-GHz bandwidth. The minimum loss is 11.5 dB at the center frequency. By replacing two of the shunt stubs with a dual-frequency in-line stub consisting of newly developed compact microstrip resonating cells (CMRCs), the performance of the SH mixer is improved significantly. At 35 GHz, the conversion loss of this new fourth SH mixer is as low as 6.1 dB with a 3-dB bandwidth of 6 GHz. The conversion loss in the whole Ka-band (26.5-40 GHz) is less than 16 dB. The proposed fourth SH mixer incorporating with CMRCs provides a low-cost high-performance solution for RF subsystem design.