Circular Polarization of Periodic Leaky-Wave Antennas With Axial Asymmetry: Theoretical Proof and Experimental Demonstration

Abstract

Abstract-This paper includes two contributions. First, it proves that the series and shunt radiation components, corresponding to longitudinal and transversal electric fields, respectively, are always in phase quadrature in axially asymmetric periodic leaky-wave antennas (LWAs), so that these antennas are inherently elliptically polarized. This fact is theoretically proven and experimentally illustrated by two case-study examples, a composite right/left-handed (CRLH) LWA and a series-fed patch (SFP) LWA. Second, it shows (for the case of the SFP LWA) that the axial ratio is controlled and minimized by the degree of axial asymmetry.Index Terms-Bloch-Floquet theorem, circular polarization (CP), composite right/left-handed (CRLH) transmission line structures, leaky-wave antenna (LWA), periodic structure, phase quadrature, series-fed patch (SFP).

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

“…Moreover, a CRLH TL even supports broadside radiation under the balanced condition. With above mentioned advantages, microstrip line based single radiator circularly polarized (CP) CRLH LWAs have been proposed [13]- [15]. The inherent quadrature phase relation of a series and a shunt radiation component for a CP radiation is analyzed in [15].…”

“…With above mentioned advantages, microstrip line based single radiator circularly polarized (CP) CRLH LWAs have been proposed [13]- [15]. The inherent quadrature phase relation of a series and a shunt radiation component for a CP radiation is analyzed in [15]. Such CP LWAs are particularly aimed for wireless application under dynamic motion, requiring high signal throughput.…”

Broadside Dual-Channel Orthogonal-Polarization Radiation Using a Double-Asymmetric Periodic Leaky-Wave Antenna

“…Moreover, from LA, both resonators can reach maximal efficiency (100% in the absence of dissipation loss), which means that maximal efficiency can be achieved from both ports. Finally, since the series and shunt resonators feature mutually orthogonal fields [14], the polarizations from the two ports will be orthogonal to each other. Specifically, the series polarization (forward direction) will be longitudinal while the shunt polarization (backward direction) will be transverse.…”

Low cost beam‐steering leaky‐wave antenna for microwave application

“…Dirac LWAs is another novel approach for stopband elimination, using degenerate eigenmodes . Also, disturbing symmetry in the unit cell (longitudinal asymmetry or transversal asymmetry) in addition to frequency balancing propose correct broadside radiation . In addition, using periodically modulated spoof plasmonic waveguide to convert guide spoof surface plasmon polaritons to radiating waves is offered in Reference that surface impedance is modulated sinusoidal by changing the depths of corrugation grooves.…”

“…[6][7][8] Also, disturbing symmetry in the unit cell (longitudinal asymmetry or transversal asymmetry) in addition to frequency balancing propose correct broadside radiation. 9 In addition, using periodically modulated spoof plasmonic waveguide to convert guide spoof surface plasmon polaritons to radiating waves is offered in Reference 10 that surface impedance is modulated sinusoidal by changing the depths of corrugation grooves. In addition to the above mention, by utilizing additional longitudinal slots as parallel components in Reference 11, periodic modulations along the Goubau line in Reference 12, two similar but nonidentical elements per unit cell in Reference 13, and the open-stopband is suppressed.…”