Compact DC to 110 GHz Crossover Based on Metallic-Nanowire-Filled Membrane

This letter presents an ultra-wideband crossover based on metallic-nanowire-filled membrane (MnM) from dc to 110 GHz. Two designs are proposed with reduced insertion loss and high isolation. Design Type 1 presents a 1.2 dB insertion loss and 19 dB isolation up to 80 GHz, with a phase imbalance of 14° at 80 GHz. This important phase imbalance is due to CPW that passes under the top microstrip (MS) line. To improve the device, a CPW was used in both paths. The improved design Type 2 shows a 1.5 dB insertion loss, 0.2 dB insertion loss imbalance, and 3.3° phase imbalance at 110 GHz. The latter presents a measured isolation of 38 dB up to 70 GHz and a simulated isolation better than 30 dB up to 110 GHz.