A Wideband W-Band Frequency Tripler With a Novel Mode-Selective Filter for High Harmonic Rejection

This paper presents a wideband W-band frequency tripler designed in an advanced 0.13-μmSiGe HBT technology. It consists of an overdriven differential class A cascode amplifier followed by a filter and a butter amplifier. The common-mode (CM) impedance at the tripler input around the 2nd harmonic is enhanced due to the dedicated design of the input balun, aiding in boosting the 3rd harmonic output power by harmonic mixing of differential fundamental with the CM 2nd harmonic at the non-linear base-emitter capacitance ($\mathrm{C}_{b\mathrm{e}}$) at the input common emitter (CE) stage. A novel mode-selective filter was developed to allow broadband tripler operation with high harmonic rejection up to the 6th harmonic. The tripler operates at 2.0 V supply voltage reaching a saturated output power of 2.5 dBm, including the balun loss of 1.5 dB, with a 3-dB fractional bandwidth of 22.5% and total power dissipation of 60 mW/60mW for tripler/butter correspondingly. The following harmonic suppression values were measured: >45dBc, >40dBc,>35dBc, >25dBc, and >50dBc for 1st, 2nd, 4th, 5th and 6th, correspondingly. The active chip area consisting of tripler, filter, and butter is 0.52 m$\mathrm{m}^{2}$.