A D-Band 5-Bit Switch-Type Phase Shifter with Low IL and Phase Error Using a Switch-Self-Phase-Shifting Unit

This paper presents a D-band 5-bit passive switch-type phase shifter that combines a compact switch-self-phase-shifting (SSPS) unit with a dual high-pass phase-shifting unit. The SSPS unit innovatively reconfigures the quarter-wavelength microstrip line embedded in the switch and its intrinsic parasitic capacitances as part of the phase-shifting network. This approach not only reduces insertion loss and phase error but also shrinks the core size by 29.6% compared to conventional true-time-delay implementations. Furthermore, a dual high-pass phase-shifting unit is introduced to mitigate the rapid phase-error growth in D-band, which is typically caused by the large capacitance and associated parasitic inductance required for fine phase steps in conventional high-pass/low-pass networks. Fabricated in a 130-nm SiGe BiCMOS technology, the prototype operates from 110 to 155 GHz. Measurement results demonstrate a measured RMS phase error below 5.89°, a peak average gain of -15.6 dB, and an average IL of 17.3 dB with a 1.7-dB variation.