Highly Isolating and Broadband Single-Pole Double-Throw Switches for Millimeter-Wave Applications Up to 330 GHz

This paper reports on the investigation, design, and fabrication of single-pole double-throw (SPDT) millimeter-wave integrated circuit (MMIC) switches for applications with an operating frequency of up to 330 GHz. An analysis of the well-established millimeter-wave (mmW) switch topology (λ/4-shunt SPDT switch) is done to achieve wideband performance and high isolation simultaneously. Using a standard technology parameter (R
_ON
), this theory allows a performance estimation of switch MMICs before a wafer run and can support the design of mmW switches. Based on this analysis, a novel switch topology, with an improved isolation, is introduced. Additionally, this paper demonstrates three SPDT switch MMICs (SPDTs 1-3), the first two of which are targeting the W-band, whereas the latter is targeting the H-band frequency range. All MMICs were fabricated on the Fraunhofer Institute for Applied Solid State Physics 50-nm gate length metamorphic high-electron-mobility transistor process. SPDT 1 achieves a bandwidth of 52-168 GHz. The average insertion loss (IL) and the isolation are 3.1 and 42.1 dB, respectively. The peak performance is 2.1 and 52 dB. SPDT 2 utilizes the novel switch topology and yields the average IL and isolation of 4.5 and 56.4 dB, respectively. The operating bandwidth is 75-170 GHz. The peak performance is 3 and 65 dB. The 1-dB compression points (P
_in1dB
) of SPDTs 1 and 2 are 19 dB and 14 dBm, respectively. SPDT 3 operates from 122 to 330 GHz and achieves the average IL and isolation of 2.2 and 17.4 dB, respectively. The peak performance is 1.5 and 22.8 dB.