Summary: A compact Ku-band 5-bit monolithic microwave integrated circuit (MMIC) phase shifter has been demonstrated. The total gate width of switching FETs and the total inductance of spiral inductors are proposed as the figures of merit for compactness. The phase shifter uses the T-type and PI-type high-pass filter (HPF)/band-pass filter (BPF) circuits in which FET "off"-state capacitances are incorporated as the filter elements. According to the figures of merit, the T-type is selected for 90-degree phase shift circuit and the PI-type is selected for the 45-degree phase shift circuit. The fabricated 5-bit phase shifter performs average insertion loss of 5.6 dB and RMS phase shift error of 3.77 degrees with die size of 1.65 mm 0.76 mm (1.25 mm2) in Ku-band.