UWB transmission characteristics of bow-tie antennas on Si

Transmission characteristics of bow-tie antennas, which were fabricated on silicon substrates, were investigated for a mobile ultrawide-band (UWB) microwave radar. Bow-tie antennas, which have different antenna lengths and flare angles, were fabricated on a Si substrate having resistivities of 10 Omegaldrcm, 79.6 Omegaldrcm and 2.29 kOmegaldrcm. Using bow-tie antennas with antenna length of 5.37 mm and flare angle of 53deg, the waveform and propagation characteristics were measured. S₂₁ increased with increasing the resistivity of Si substrate, and S₂₁ of -20 dB was obtained for bow-tie antennas with 10 mm distance fabricated on Si chip having the resistivity of 2.29 kOmegaldrcm.