Experimental results obtained on a new circuit topology of a broadband and low spurious frequency doubler

A CRLH (Composite Right-/Left-Handed) based distributed frequency multiplier circuit topology is proposed. It is demonstrated that using fully-distributed CRLH based unit cells, low spurious output spectrum and flat output power level may be obtained for a large frequency bandwidth. To validate the proposed frequency multiplier, a frequency doubler is designed and fabricated. The experimental results have shown that the conversion losses on the output second harmonic is less than 9 dB and 7 dB, for input power level of -1 dBm and 5 dBm, respectively, within an input frequency bandwidth from 4 GHz to 6 GHz. In the same frequency bandwidth, due to the CRLH based circuit topology, the first and third output harmonics are well filtered.