2012 Volume 9 Issue 5 Pages 391-396
In this letter, a wideband push-push VCO using two types of phase shifters is presented. A positive feedback type push-push oscillator is used for the VCO. The phase shifters are connected in series in each feedback loop. Varactor diodes are used in the phase sifters for the frequency tuning. In the VCO, the oscillating frequency can be changed widely as much phase shift is achieved by the sum of phase shift of each phase shifter connected in series. In the experiment, the developed push-push VCO designed in K-band achieves wide tuning frequency range of 1.88GHz(relative bandwidth = 8.9%) in K-band with small variation of the output power.