We designed and fabricated a low-bias operational uni-travelling carrier photodiode (UTC-PD) structure, which can be operated at over 100 GHz. The main structure of the device consisted of p-doped InGaAs for the photo-absorption layer and non-doped InP for the carrier collector layer, to obtain both a high electron drift velocity at a low bias and a small CR time constant based on the pn-junction capacitance. Through an on-wafer probing test, the frequency response was measured up to 210 GHz using a 1 mm coaxial connecter type (DC-110GHz), W-band (75-110 GHz) and G-band (140-220 GHz) waveguide probe with a spectrum analyzer. In the measurement results, a large bandwidth of 10 MHz-110 GHz could be obtained with good flatness within ±1 dB. When the W-band and G-band performance were characterized, the high-power characteristic of -3.8 dBm could be achieved at 106 GHz. and the output power level of - 19.8 dBm could be confirmed at 210 GHz as well.