A 0.95 dB Insertion Loss Compact Ultra Wideband Millimeter-Wave Bandpass Filter Using 0.18 $\mu \mathrm{m}$ RF CMOS Technology

A 57 GHz ultra-wideband (UWB) bandpass filter with record low insertion loss of 0.95 dB occupying only 90 ×90μm
²
is reported in this letter. A 0.18 μm RF CMOS process using a single thick metal is used for realizing the filter. Layout optimized spiral inductors, metal-insulator-metal and inter digital capacitors are used in the design. The fabricated UWB millimeter-wave filter has a measured 3 dB bandwidth of 58 GHz with center frequency of 57 GHz. Return loss greater than 10 dB is observed through out the passband, while 20 dB return loss is seen for a significantly larger ( ≥ 70 %) fraction of the passband. Excellent agreement between measured results and electromagnetic simulations is achieved. Robustness of the designed filter against CMOS process parameters is examined through monte-carlo simulations.