Open AccessLow phase‐noise X‐band oscillator based on elliptic filter and branchline coupler
Author(s) -
Nimehvari Varcheh Hamed,
Rezaei Pejman
Publication year - 2019
Publication title -
iet microwaves, antennas and propagation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.555
H-Index - 69
eISSN - 1751-8733
pISSN - 1751-8725
DOI - 10.1049/iet-map.2018.5336
Subject(s) - phase noise , vackář oscillator , dbc , variable frequency oscillator , offset (computer science) , planar , microwave , local oscillator , physics , electrical engineering , optoelectronics , electronic engineering , materials science , engineering , computer science , telecommunications , computer graphics (images) , programming language
This paper presents a procedure for designing of a very low phase‐noise (LPN) X‐band planar microwave oscillator based on a closely packed four‐pole elliptic band‐pass filter as a frequency stabilisation section. The elliptic band‐pass filter as improving phase‐noise is realised, and branchline coupler as a key factor in the feedback loop is introduced. The design method to obtain LPN applications for optimum performance is presented. As a proof of concept, the X‐band oscillator employing a packaged GaAs FET transistor is designed and measured. The oscillator, operating at 8.172 GHz, exhibits a measured phase‐noise of −160 dBc/Hz at 1‐MHz frequency offset with 4 dBm output power. To the best of authors’ knowledge, this oscillator indicates the lowest phase‐noise in the class of published X‐band planar oscillators, to date.