CAD of coaxially end‐fed waveguide phased‐array antennas

Abstract

An alternative configuration for an infinite coaxially end- fed waveguide phased-array antenna is explored. In the proposed con- figuration, the integration of the end-fed launcher and the output waveguide, rather than the waveguide in itself, acts as a basic radiator. This allows the design of more compact antenna elements. In order to analyze and optimize the structure, an accurate full-wave simulation tool based on the multimode admittance matrix representation is developed. Results are validated against state-of-the-art commercial CAD software. Numerical simulations involving singly and doubly tuned con- figurations are presented and discussed to illustrate the potential convenience of the proposed configuration and of the CAD tool developed

Coaxial End-Launched and Microstrip to Partial <formula formulatype="inline"><tex Notation="TeX">$H$</tex></formula>-Plane Waveguide Transitions

“…The L-shaped loop transition does not necessarily require the post for operation [10] and it is only used when wider bandwidths are required from a doubly tuned structure [11]. Note that the probe part of the transition in both the rectangular (a) and partial H-plane (b) waveguides in Fig.…”

“…2) and probe part. A match can be achieved using three different methods, firstly the L-shaped loop can be move slightly off the centre line [10], secondly the T-line part can be extended slightly beyond the probe part [12] and lastly the contact position of the transmission line and probe parts can be varied up and down the probe's length to achieve a match [11]. The varied contact matching technique is used as all of its geometry lie along the centre line of the waveguide and it can achieve a wider bandwidth compared to the extended T-line method [7].…”

Patch end-Launchers-a family of compact colinear coaxial-to-rectangular waveguide transitions

“…As already anticipated in [5], the concept at the basis of the patch end-launcher can be extended to multiply tuned configura- tions by employing a strategy that is reminiscent of the approach used for designing the doubly tuned loop launcher described in [4]. Basically, it amounts to optimizing the matching between the structure's input and output ports at a number of relatively closely spaced frequencies such that to broaden the frequency band of operation.…”

“…In such cases, the use of the standard, right-angle coaxial-to-rectangular waveguide transitions is highly inadequate, the traditional solution being that of employing coaxial, L-shaped loop launchers [1]- [4].…”