A Novel Technique for Open-Stopband Suppression in 1-D Periodic Printed Leaky-Wave Antennas

Abstract

A novel technique for the elimination of the open stopband in one-dimensional periodic printed leaky-wave antennas is presented. A quarter-wave transformer, or alternatively a matching stub, is introduced into the unit cell of the antenna, which forces the Bloch-wave impedance of the structure to remain real and non-zero at broadside. The effectiveness of the proposed technique is first demonstrated on a printed periodic microstrip leaky-wave antenna consisting of a single radiating stub per unit cell, which exhibits a significant stopband at broadside. The technique is then also applied to a structure consisting of two radiating stubs per unit cell, which is capable of mitigating, but not eliminating, the open stopband. In both cases the open stopband at broadside is completely suppressed

Dirac leaky-wave antennas for continuous beam scanning from photonic crystals

“…Periodic LWAs typically have a rise in |S 11 | near the broadside frequency (referred to as increased voltage standing wave ratio) 10,23 , which becomes more serious with increasing the antenna length (the closer they approach to the infinitely periodic case). This is definitely not the case here and hence this is one of the indications that the DLWA is markedly different.…”

“…Elimination of the open stopband in one-dimensional (1D) periodic printed LWAs at microwaves was demonstrated in ref. 23, using a stub-matching technique in the unit cell. These concepts have so far been demonstrated only at microwaves.…”

“…These concepts have so far been demonstrated only at microwaves. Primarily this is because they are either applicable to periodic structures with a very subwavelength unit cell period (( l g ) such as transverse electromagnetic (TEM) and quasi-TEM mode (mainly microstrip type) LWAs, or require situations where it is possible to realize printed circuit or stub elements, or more complicated unit cells with additional mechanisms 22,23 , and/or situations where it is appropriate to apply transmission-line modelling as in refs [19][20][21][22] to determine the balanced condition and close the stopband.…”

A Compact Single Radiator CRLH-Inspired Circularly Polarized Leaky-Wave Antenna Based on Substrate-Integrated Waveguide

“…antennas (LWAs) have attracted researchers for many years because of their unique frequency beam scanning capability and broad operational bandwidth [1]- [7]. Recent birth of metamaterial transmission line concept has even further accelerated the study of leaky-wave antennas [8]- [12].…”

Numerical Evaluation of Electromagnetic-wave Penetration at Normal Incidence through an Inhomogeneous-wave Approach

“…Twodimensional and periodic leaky-wave antennas have the advantage of creating a pencil beam at broadside, which is the direction of interest here, employing a very simple feeder. A mono-dimensional and periodic antenna could also represent a suitable solution because, even though those structures present a natural stop-band at broadside [3], [4], examples are present in literature of projects that can guarantee broadside radiation employing those structures [14], [15]. Anyway, the mono-dimensional periodic LWAs still require challenging design for achieving the stop-band suppression at broadside.…”