A 60-110 GHz low conversion loss tripler in a 0.15-μm InGaAs metamorphic high electron-mobility transistor (MHEMT) technology is presented in this paper. The tripler employs a configuration of an anti-parallel diode pair to produce the third harmonic signal. Between 60 and 110 GHz, this tripler features a conversion loss of less than 20 dB with an input power of 15 dBm. The minimum conversion loss is 13 dB at 81 GHz with an output power of 3 dBm. The output 1-dB compression point (P1dB) is higher than 3 dBm among the operating bandwidth. The output power is higher than 4 dBm while the driving power is 20 dBm. The overall chip size is 1x1 mm2. To the best of the author's knowledge, this is the highest output power MMIC-based diode tripler to cover the entire E- and W-band without dc power consumption.