Analysis of Connected Arrays and Capacitively Coupled Arrays

Abstract

The concept of connected and capacitively coupled dipoles in a planar array, which improves wideband performance, is investigated. A long wire with multiple feeds acts as an array in connected arrays, whereas a capacitively coupled array uses capacitors between array elements. Both approaches attempt to approximate the current sheet of Wheeler. Using spectral Green's function, the array active impedance is calculated. The impedance mismatch of a connected/capacitively coupled dipole array is less than that of an array of unconnected dipoles of the same size. Both direct and capacitive connections can be used to design a wideband array antenna with a ground plane, although capacitive coupling performs better than a direct connection. This fact resulted from numerous analytical studies using infinite dipole array scan (active) impedance endorsed by full-wave simulations using CST MWS. The maximum mismatch losses over the frequency band for different source (reference) impedances are used to find the best solution at the broadside. To consider the scan performance, the average reflected power over all scan angles is applied, and then, the maximum average mismatch loss over the frequency band is investigated.

Analysis of tightly-coupled dipole phased array antennas with metasurface superstrate

“…These relations do not work for TCDAs. So, we use scan impedance relations developed for the connected arrays based on spectral Green's function 8 , 25 .…”

“…In tightly-coupled dipole arrays, antenna elements are coupled to each other to achieve a continuous current distribution. Coupling between dipoles is either capacitive or direct 8 . Tightly-coupled dipole arrays(TCDAs) can achieve wide bandwidths up to 5:1 and more 9 , 10 .…”

Analysis of Tightly-Coupled Dipole Phased Array Antennas with Metasurface Superstrate

“…These relations do not work for TCDAs. So, we use scan impedance relations developed for the connected arrays based on spectral Green's function [8,23].…”

“…The unit-cell size in 𝑥 and 𝑦 are 𝑑 𝑥 and 𝑑 𝑦 , respectively. The analysis of the TCDA is based on [24,25] and a brief review of the scan impedance derivation is stated in [8]. The current distribution of the array is derived by enforcing the E-field continuity boundary condition, and the scan impedance is found to be…”

“…In tightly-coupled dipole arrays, antenna elements are coupled to each other to achieve a continuous current distribution. Coupling between dipoles is either capacitive or direct [8]. Tightly-coupled dipole arrays(TCDAs) can achieve wide bandwidths up to 5:1 and more.…”