A D-Band 180° phase shifter with very low amplitude- and phase-error

Phase shifters are at the heart of phased array systems which enable beam steering techniques. This paper presents a 180° digital phase shifter MMIC employing two SPDT switches which are realized in a 50 nm metamorphic high electron mobility transistor technology. For the phase difference generation two identical couplers with different terminations are used. The measurement results show only 0.1 dB amplitude imbalance and less than ±3.5° phase imbalance between 115 and 155 GHz. The transmission loss is less than 5.6 dB and the input and output matching are better than -10 dB in the considered frequency range. The fabricated chip-size is 1.25 × 0.75 mm² including the test pads.