Harmonics suppression of Wilkinson power divider using spurlines with adjustable rejection bands

A newly asymmetrical spurline structure is presented in this letter. Its dual-bandgap characteristics are reported and can be adjusted by changing the length difference between spurlines. Then, a simple circuit model is set up for the spurline structure by using two LCR-resonators and the circuit parameters can be extracted from EM simulations. Moreover, a Wilkinson power divider using the proposed spurlines was designed, fabricated, and measured. Experimental results verify that 27-dB suppression for the second harmonic and 30-dB suppression for the third harmonic are obtained, respectively. In addition, the reflection coefficient are −3.5 dB ± 0.3dB below 3.8 GHz and −3.7 dB at the operating frequency 3.12 GHz.