Low phase noise oscillator employing miniaturized shielded-EMSIW resonators embedded with CSRRs structure

In this paper, a parallel-feedback oscillator exploiting miniaturized shielded eighth mode substrate integrated waveguide (SD-EMSIW) resonators embedded with complementary split-ring resonators (CSRRs) structure is proposed. The phase noise performance of the designed oscillator can be efficiently enhanced by employing the SD-EMSIW resonators. Meanwhile, the physical size is prominently miniaturized by loading the CSRRs. The proposed oscillator is designed at 3.5 GHz by utilizing a four-order quasi-elliptic bandpass filter (BPF), combining the shielding metallized walls and etched CSRR techniques on the EMSIW cavities. The proposed prototype has been designed, fabricated and experimented. The experimental results indicate that the oscillator operates at 3.52 GHz with an output signal of 4.2 dBm. The second-harmonic suppression reaches to 25.2 dBc. The phase noise performance of the proposed oscillator features −134.8 dBc/Hz at 1-MHz frequency-offset. In addition to the property of the low phase noise, the proposed prototype exhibits the merits of miniaturized dimension and effective shielding characteristic.