Design of coaxial line-to-circular waveguide transitions

Abstract

Coaxial line-to-circular waveguide transitions are characterised by numerical modelling supported by experimental verification. Various coaxial line to waveguide diameter ratios have been considered, and the effects of parameter variations have been studied. It has been found that both narrowband matching at a specific frequency and broadband matching over the entire operating frequency band can be achieved. The optimum parameters for such transitions are reported.

Computational Design of an In-Line Coaxial-to-Circular Waveguide Adapter with More Than an Octave Bandwidth

“…In a coaxial-to-metallic waveguide adapter, the conversion between the coaxial TEM mode to the fundamental waveguide mode has been realized using a simple cylindrical probe [9], a disc probe [10], a conical probe [11] and a stepped-ridge converter [12,13]. In most of the existing works on CCWAs, right-angle structures have been employed, where the coaxial cable axis is perpendicular to the circular waveguide axis, as indicated by the studies of [14][15][16]. Bang and Ahn presented a wideband, right-angle CCWA that operates from 1.04 to 2.53 times the TE 11 -mode cutoff frequency of the circular waveguide, with a reflection coefficient of less than −20 dB [11].…”

Design of a Circular Waveguide to Coaxial Cable Transition Employing a Printed Dipole

“…원형도파관은 반사경 안테나 피드, 직교모드변환기, 편파기, 필터/ 멀티플렉서, 로터리 조인트 등의 구현에 널리 사용 되고 있다 [1]- [4]. 원형도파관을 송신기 또는 수신기 에 연결하기 원형도파관-동축선 변환부가 요구되며 기존 연구결과로서 단순한 동축선 프로브를 이용한 구조(동작범위 2.3~2.7GHz) [5], 이중 리지를 이용한 구조(동작범위 0.83~2.8GHz) [6], 단순 동축선 프로브 를 이용한 구조(동작범위 8.8~10.9GHz) [7], 원뿔 프 로브와 사각형-원형도파관 변환부를 이용한 구조(동 작범위 7.34~17.77GHz) [8] 등이 발표되었다. 사각도 파관-동축선 변환부에 많은 연구 결과가 발표되었 으며 도파관이 동작하는 전 주파수 대역에서 동작 하는 변환부의 설계가 가능하다.…”

Coaxial‐to‐circular waveguide transition with broadband mode‐free operation

“…In the design of a broadband circular-to-coaxial transition, one is faced with two important tasks: the design of a lowreflection coaxial cable and the suppression of higher modes. Contrary to the case of a rectangular-to-coaxial transition, published works on the circular-to-coaxial transition are quite limited [1][2][3]. A simple coaxial probe feeding a circular waveguide shows a narrow-band performance [1,2].…”

“…Contrary to the case of a rectangular-to-coaxial transition, published works on the circular-to-coaxial transition are quite limited [1][2][3]. A simple coaxial probe feeding a circular waveguide shows a narrow-band performance [1,2]. A double-ridged structure offers wideband performance although it is structurally complicated [3].…”

“…1b shows a structure that can be inserted into a circular waveguide for easy fabrication. A direct excitation of a circular waveguide by a coaxial cable usually results in a narrow bandwidth [1,2]. On the basis of the observation that a wideband operation is possible with a rectangular-to-coaxial transition [4], we first form a transition from a coaxial cable to a rectangular waveguide and then make a transition from the rectangular waveguide to the circular waveguide.…”