Design of a Wideband and High Isolation Millimeter-Wave GaN Monolithic Integrated Switch Using Bandpass Matching Network

This work presents a novel bandpass matching network (BMN)-based switch design methodology. Theoretical analysis shows that, compared to conventional low-pass matching network (LMN)-based designs, the proposed approach enables the upward shift of the operating band while maintaining impedance matching and enhancing isolation. This makes the method particularly suitable for realizing wideband, high-frequency switches with high isolation in semiconductor technologies with limited transition frequency (fT). To validate the concept, a seventh-order single-pole single-throw (SPST) switch was designed and fabricated using a 0.15 μm GaN-on-SiC process with a nominalfTof 35 GHz. Measurement results show that the proposed switch achieves an insertion loss below 2 dB and isolation greater than 33 dB across the 15–40 GHz band. Moreover, the design demonstrates excellent linearity, with a measured third-order input intercept power of 49-52 dBm.