A novel frequency doubler using feedforward technique and defected ground structure

A novel design of frequency doubler using feedforward technique and defected ground structure (DGS) is proposed. The feedforward loop in the proposed frequency doubler suppresses the fundamental component (f/sub o/), and the DGS diminishes the higher order harmonics such as third, fourth, and so on. Due to the combination of feedforward structure and DGS, only the doubled frequency component (2f/sub o/) appears at the output port and the other unwanted components are suppressed excellently. A frequency doubler is designed at 1.85GHz of f/sub o/ by the proposed technique and measured. The measured output power of 2f/sub o/ is -3 dBm when the input power is 0 dBm. The obtained suppression of f/sub o/, 3f/sub o/, and 4f/sub o/ are 42.9, 19.2, and 29.7dB, respectively.