Analysis and Design of a Compact Leaky-Wave Antenna for Wide-Band Broadside Radiation

A low-cost compact planar leaky-wave antenna (LWA) is proposed offering directive broadside radiation over a significantly wide bandwidth. The design is based on an annular metallic strip grating (MSG) configuration, placed on top of a dual-layer grounded dielectric substrate. This defines a new two-layer parallel-plate open waveguide, whose operational principles are accurately investigated. To assist in our antenna design, a method-of-moments dispersion analysis has been developed to characterize the relevant TM and TE modes of the perturbed guiding structure. By proper selection of the MSG for a fabricated prototype and its supporting dielectric layers as well as the practical TM antenna feed embedded in the bottom ground plane, far-field pencil-beam patterns are observed at broadside and over a wide frequency range, i.e., from 21.9 GHz to 23.9 GHz, defining a radiating percentage bandwidth of more than 8.5%. This can be explained by a dominantly excited TM mode, with low dispersion, employed to generate a two-sided far-field beam pattern which combines to produce a single beam at broadside over frequency. Some applications of this planar antenna include radar and satellite communications at microwave and millimeter-wave frequencies as well as future 5G communication devices and wireless power transmission systems

In-plane modal analysis of a metalayer formed by arrayed pairs of dogbone-shaped conductors

We present a comprehensive analysis of natural modes of a planar metamaterial layer (metalayer) formed by arrayed pairs of metallic dogbone-shaped conductors separated by a thin dielectric layer. The in-plane modes are classified based on the symmetric and anti-symmetric current distributions in the pairs. Of particular interest are the anti-symmetric modes, since the anti-symmetric current is associated with the magnetic resonance in metamaterial particles made of tightly coupled pairs. It is shown that the modal spectrum includes both TE and TM bound (proper real) and leaky (proper complex and improper complex) modes. An interesting observation is that a peculiar dominant TM improper leaky wave with a low attenuation constant, for the anti-symmetric current distribution, occurs at low frequencies, with a potential application in periodic leaky-wave antennas. © 2011 Elsevier B.V

In-plane modal analysis of a metalayer formed by arrayed pairs of dogbone-shaped conductors

We present a comprehensive analysis of natural modes of a planar metamaterial layer (metalayer) formed by arrayed pairs of metallic dogbone-shaped conductors separated by a thin dielectric layer. The in-plane modes are classified based on the symmetric and anti-symmetric current distributions in the pairs. Of particular interest are the anti-symmetric modes, since the anti-symmetric current is associated with the magnetic resonance in metamaterial particles made of tightly coupled pairs. It is shown that the modal spectrum includes both TE and TM bound (proper real) and leaky (proper complex and improper complex) modes. An interesting observation is that a peculiar dominant TM improper leaky wave with a low attenuation constant, for the anti-symmetric current distribution, occurs at low frequencies, with a potential application in periodic leaky-wave antennas. © 2011 Elsevier B.V

Surface-wave propagation in a metamaterial formed by arrayed pairs of planar conductors

Abstrac

Analysis and design of planar periodic leaky‐wave antennas

This chapter focuses on the general properties of planar periodic leaky-wave antennas, and presents an accurate and versatile method for analyzing this class of structures using the method of moments together with a mixed-potential integral equation form of the electric field integral equation. This type of antenna structure consists of a planar periodic metallization on a grounded substrate, and is thus low in profile and simple to fabricate. Depending on the frequency, radiation may occur in either the backward or the forward directions. One important advantage of the proposed method of analysis is that it allows for a complete characterization of the modal propagation on the structure, including all possible propagation and radiation regimes

Matching techniques for efficient broadside radiation in 1-D periodic printed leaky-wave antennas

Symmetric pi-matching networks are presented for suppressing the open stopband (OSB) and obtaining efficient broadside radiation in one-dimensional (1-D) periodic printed leaky-wave antennas (LWAs). The elimination of the OSB is achieved by matching the Bloch-wave impedance of the structure to a desired (non-zero) value at broadside frequency. Three different matching conditions can be applied. The effectiveness of the proposed techniques are demonstrated with numerical simulation on real structures