The Multiple Branch Waveguide Coupler

A design of novel grooved circular waveguide polarizers

“…Here, on the occasion of inciding a dominant mode to the four-port device, low return loss, high isolation between two orthogonal modes at input port, 3dB power splitting and 90degree differential phase-shifting between two orthogonal modes at output port are in demand for polarizer performance. Therefore, it is considered that the well-known design method of the branch waveguide 3dB directional coupler can be applied to the design of the polarizer [3,4]. Fig.2 illustrates the design concept of the grooved circular waveguides.…”

“…According to the design of the 3dl3 directional coupler with n-branches, each size of groove is determined by satisfying the following coupling (2) where AI is each scattering parameter s 3 1 (i.e., coupling voltage amplitude) of two end grooved waveguides, ZI is corrected end branch guide impedance, Az is each scattering parameter S31 of n-2 center connecting grooved waveguides and ZZ is corrected center branch guide impedance. Corrected branch guide impedance ZI and Z2 are solutions for the 3dB directional coupler with nbranches, which give a perfect input match at the centn frequency within the assigned operating band [3]. And further, each space between grooved waveguide centers I. is determined by where is the common circular waveguide wavelength of the fundamental mode at the center eequency.…”

“…A discontinuity is given by the link of a circular waveguide to parallel-plate radial waveguide junction and a radial cavity with two rectangular waveguides [5]. For example, by the application of the resonator method- [6], the electromagnetic fields in regions (l), (Z), (3), (4) are the unknown coefficients that can be expressed as a function of the above normalization terms, propagation constants and amplitude vectors. The electromagnetic fields in respective regions of E-plane cross-junction are similarly derived, too [5].…”

“…The presented polarizer is suitable for realizing high performance and low fabrication cost in Ka-band and above because of simple structure without corrugated components, metallic posts, and a dielectric slab taper. And further, we propose a convenient design method of the grooved circular waveguide polarizer, which applies the well-known design method of the branch waveguide coupler [3,4]. The design method is accurately performed using 111-wave mode-matching techniques for circular-torectangular waveguide cross-junctions [5].…”

Mono-grooved circular waveguide polarizers

“…The grooved circular waveguide polarizer is suitable for realizing high performance and low fabrication cost in the Ka-band and above. The design method of the polarizer applies in the well-known design method of the branch waveguide coupler [4], and the design is performed by the full-wave analysis of circular-to-remgular waveguide T-junction or cross-junction using modematching techniques. In practice, Ka-band grooved circular waveguide polarizers fabricated with the aid of the analysis and design techniques had realized excellent performance without tuning elements [3].…”