Design of Frequency Doubler Using Inductively Compensated Microstrip Ring Resonator

This paper presents a simple design technique of resistive frequency doubler by using a microstrip square ring resonator based on inductively compensated parallel-coupled lines as an output stage. The proposed topology with simple design equations is demonstrated with the input and output frequencies of 0.9/1.8 GHz and less than 3.2 dB insertion losses. More than 26 and 22 dB of spurious suppression performance at the 2nd and 3rd harmonics frequencies are obtained from the experimental results. The capability of the proposed square ring resonator was demonstrated by employing as the output stage of the resistive frequency doubler to enhance the suppression performance of circuit. The measured result of 0.9/1.8 GHz input and output signal frequency doublers is shown with the exhibit more than 40 dB suppression at frequencies 0 f and 0 3f below the desired requency 0 2f and the conversion loss is less than 12.6 decibel.