A compact ×2 frequency multiplier covering all ku band is implemented in IBM 0.13μm SiGe technology. The transformer coupled circuit uses a common base configuration working in B- class mode and utilizes transmission lines properties to achieve harmonic suppression. The doubler covers a 3dB frequency range between 12.2 GHz to 20.4 GHz with a saturated output power above 9 dBm. The fundamental frequency is suppressed by over 27 dBc and the 4th harmonic is suppressed by more than 25 dBc across frequency band. The core design occupies only 550 μm × 620 μm and consumes 37 mW from a 2.7 V supply. © 2014 IEEE.