Dual-Port Phase Antenna and Its Application in 1-D Arrays to 2-D Scanning

A novel dual-port phase antenna is proposed to realize 2-D scanning. The antenna consists of two monopoles on both sides and a fishbone structure in the middle. By changing the phase difference
${\Delta \varphi }$
between two monopoles, energy is coupled to the proposed structure, exciting different degrees of superposition of even and odd modes. The continuous switching from the broadside lobe to the end-fire lobe is realized, and it has the characteristic of 2-D scanning. Furthermore, to provide an in-depth insight into the 2-D scanning mechanism, two linear arrays (Array 2 and Array 3) based on the proposed antenna element and a generalized principle of pattern multiplication (GPPM) are developed. The fabricated Array 2 can offer scanning angles of 0°–73° along the
$\theta $
-direction with the gain of 6.5–10.4 dBi and 90°–140° along the
$\Phi $
-direction with the gain of 6.1–11.7 dBi. Its scanning coverage of 3 dB beamwidth is
$0^{\circ } < \Phi < 140^{\circ }$
,
$0^{\circ } < \theta < 90^{\circ }$
. The manufactured Array 3 can scan 0°–90° along
$\theta $
-direction with the gain of 8.2–11.1 dBi and 50°–90° along the
$\Phi $
-direction with the gain of 6–9.36 dBi, and its 3 dB coverage of the main beam scanning is
$0^{\circ } < \Phi < 180^{\circ }$
,
$0^{\circ } < \theta < 90^{\circ }$
. Consequently, the proposed antenna and GPPM can be readily extended to wide-angle scanning phased arrays.