A Compact Single Stage Negative Resistance Oscillator with Improved Harmonic Suppression Using Co-Design Concept

This paper presents a co-design concept for a negative resistance oscillator using FET for improved harmonic rejection. The co-design concept allows to use a single section to obtain the required terminating impedance for oscillation as well as filtering function for harmonic suppression. Thus, it provides a compact configuration. A prototype is fabricated for experimental verification at 2.4 GHz. A comparison with recently published works on harmonic suppression shows an improvement of second harmonic suppression. In addition, the third harmonic is also suppressed by at least 75 dB. No source feedback and extra filter at output is used. It provides a measured output power of 5.01 dBm at f
₀
= 2.374 GHz. Detail design steps are presented.