Study on the frequency tunable ability of the varactor-loaded resonator

This work presents a study on frequency tunable ability based on varactor-loaded quarter wavelength uniform-impedance resonator (UIR). The quantitative analysis of the tunable range of the fundamental resonant frequency (→
₁
) versus capacitance under different varactor-located position along the proposed quarter wavelength UIR is given. The methods of realizing the bidirectional tuning of →
₁
and independent tuning of →
₁
without affecting the third harmonic are presented. Accordingly, the analysis and calculated results are provided in detail.