"How to design RF circuits" - oscillators

Low‐phase noise oscillator utilising high‐Qactive resonator based on substrate integrated waveguide technique

“…In previous works, to design an oscillator, the widely used approach is based on the non-linear model of the active device [16][17][18], which is convenient and relatively accurate, and the oscillator performances can be fully predicted, but the non-linear model is indispensable. The second approach relies on the linear S-parameters of the active device [22,23,28], which is quite simple and applicable for those commercial transistors with only small-signal S-parameter provided. However, there are still some design issues to be explored for the second approach: in [28], the oscillator design method does not include the PN optimisation process; in [22], the Bode plot can be used for PN optimisation only for the feedback-loop oscillators design and not suitable for the negative-resistance oscillator; in [23], for the negative-resistance oscillator design, the optimum PNCs are summarised as follows:…”

“…Thus, a negative-resistance oscillator design can be summarised as this: firstly, using method in [28] to obtain a set of L values (the microstrip length between the active device and the resonator circuit) to satisfy the oscillating conditions; secondly, setting L as the variable, the PNC value can be obtained from S-parameter simulation with advanced design system. According to the peak PNC value, the optimum L can be determined, and a low-PN SIW oscillator can be expected.…”