Title :
Variable toroidal ferrite phase shifter
Author :
Abuelma´atti, A. ; Zafar, J. ; Khairuddin, I. ; Gibson, A.A.P. ; Haigh, A. ; Morgan, I.
Author_Institution :
CoM DEV Eur. Ltd., Aylesbury
fDate :
3/1/2009 12:00:00 AM
Abstract :
Careful design of the magnetic bias circuit used in ferrite phase shifters can help to reduce space, weight and energy consumption. Low reluctance circuits must avoid air-gaps and this can be achieved using toroidal-shaped ferrite inserts positioned inside a rectangular waveguide. Here, these ferrite inserts are fabricated using a viscous plastic processing method that avoids machining and produces a continuous magnetic circuit. Finite-element methods are used to initially model the magnetostatic solution for the bias circuit before being used to analyse the microwave performance of a double toroid phase shifter. A closed-form technique is introduced to model the dielectric slab waveguide impedance transformer. The final insertion loss was < 1 < dB over the 9.5 < 10.3 <GHz band and return loss of 20 < dB was achievable. The phase shift calculation agrees to within 10< of the measured values.
Keywords :
dielectric waveguides; ferrite phase shifters; finite element analysis; impedance convertors; magnetic circuits; microwave phase shifters; rectangular waveguides; air-gaps; closed-form technique; continuous magnetic circuit; dielectric slab waveguide impedance transformer; energy consumption; finite-element methods; low reluctance circuits; magnetic bias circuit; rectangular waveguide; return loss; variable toroidal ferrite phase shifter; viscous plastic processing method;
Journal_Title :
Microwaves, Antennas & Propagation, IET
DOI :
10.1049/iet-map:20080046