Low phase noise microwave oscillator with greater than 60 dB second‐harmonic suppression

Abstract

This study presents a microwave oscillator in which an innovative hybrid microstrip and substrate integrated waveguide filter is proposed for phase noise reduction. By virtue of equivalent circuit, the specific topology of this filter is clearly revealed and verified by both the simulation and the experiment. It can realize a third-order elliptic bandpass response with two transmission zeros near the passband. Specific phase response can be formed, in which a high group delay can be achieved within a narrow frequency range around the centre frequency. This feature makes the filter performance very flexible for its application in microwave oscillator, and then reduces its phase noise. For demonstration, an oscillator example at 9.0 GHz was deigned, fabricated and measured. The measured phase noise at 100 kHz away from the oscillation frequency is as low as −120.06 dBc/Hz. Furthermore, the proposed oscillator is featured by greater than 60 dB second-harmonic suppression and at least the third harmonic is suppressed.This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

Class‐F power oscillator based on complementary split ring resonator for sub‐6 GHz fifth generation and multistandard applications

“…By combining the filter theory and network transformations (condition of oscillation), it is possible to construct a power oscillator with impedance matching and harmonic tuning that leads to high-efficiency power oscillators. As compared to the previously reported power oscillator in literature, [10][11][12][13] the suggested power oscillator characterizes an output power equal to 13.3 dBm, and phase noise of À109.3 dBc/Hz at an offset frequency of 1 MHz under a DC voltage supply of 2 V. As opposed to the previously reported state-of-the-art power oscillators, our suggested 2.45 GHz power oscillator characteristics are maximum efficiency, large power, and acceptable figure of merit (FOM). All the structures in this paper are simulated by employing the simulation tools 3D EM CST and Keysight Advanced Design System (ADS).…”

“…Ortigueira et al 12 Chang et al 10 Xu et al 11 Shu et al 13 Yang et al 16 Xu et al 17 This work resonator (CSRR) and two coupled transmission lines. Utilizing the harmonics elimination resonators, its stopband is adjustable by adopting the dimension parameters of the two resonators.…”

“…In Chang et al, 10 2.5 GHz class‐E oscillator utilizing 0.5‐μm GaAs technology was designed and achieved an FoM of −192 dBc/Hz. Xu et al 11 presented a microwave oscillator depending on a SIW filter, whose oscillation frequency is 9 GHz and the phase noise is −120 dBc/Hz at 100 KHz. A 2.4 CMOS relaxation oscillator was designed with FoM of −161.7 dBc/Hz in Ortigueira et al 12 while a large efficiency power oscillator utilizing a transformer‐based matching circuit resonator was introduced by 45 nm CMOS in Shu et al 13 In this study, a micro‐strip bandpass filter is based on coupled open‐loop resonators.…”

Low power and low phase noise complementary voltage controlled oscillator optimised by a meta‐heuristic algorithm

“…Two popular topologies for this purpose, are cross-coupled and Colpitts oscillators. Compared to cross-coupled oscillators which have good startup condition and ease of implementation, the Colpitts topologies suffer from poor startup condition while potentially have lower phase noise (PN) due to their superior cyclostationary noise properties [1][2][3][4]. Recently, there have been more attempts to design Colpitts VCOs with the suitable characteristics especially more improvement of startup condition [1].…”