Surface scattering antennas provide adjustable radiation fields by adjustably coupling scattering elements along a wave-propagating structure. In some approaches, the scattering elements are patch elements. In some approaches, the scattering elements are made adjustable by disposing an electrically adjustable material, such as a liquid crystal, in proximity to the scattering elements. Methods and systems provide control and adjustment of surface scattering antennas for various applications.

Surface scattering antenna improvements

Composite right/left-handed (CRLH) substrate integrated waveguide (SIW) and half mode substrate integrated waveguide (HMSIW) leaky-wave structures for antenna applications are proposed and investigated. Their propagation properties and radiation characteristics are studied extensively. Their backfire-to-endfire beam-steering capabilities through frequency scanning are demonstrated and discussed. These metamaterial radiating structures are realized by etching interdigital slots on the waveguide surface and the ground. The slot behaves as a series capacitor as well as a radiator leading to a CRLH leaky-wave application. Four antennas are fabricated, measured, and analyzed, including two balanced CRLH SIW designs characterized by single-side or double-side radiation, and two unbalanced HMSIW designs characterized by different boundary conditions. Antenna parameters such as return loss, radiation patterns, gain, and efficiency are all provided. Measured results are consistent with the simulation. All these proposed antennas possess the advantages of low profile, low cost, and low weight, while they are also showing their own unique features, like high directivity, quasi-omnidirectional radiation, miniaturized size, continuous beam-steering capabilities covering both the backward and forward quadrants, etc., providing much design flexibility for the real applications.

Composite Right/Left-Handed Substrate Integrated Waveguide and Half Mode Substrate Integrated Waveguide Leaky-Wave Structures

Described embodiments include an antenna system and method. The antenna system includes a surface scattering antenna that has an electromagnetic waveguide structure and a plurality of electromagnetic wave scattering elements. The plurality of electromagnetic wave scattering elements are distributed along the waveguide structure, have a respective activatable electromagnetic response to a guided propagating electromagnetic wave, and produce a controllable radiation pattern. A gain definition circuit defines a radiation pattern configured to acquire a possible interfering signal. The defined antenna radiation pattern has a field of view covering at least a portion of an undesired field of view of an associated antenna. An antenna controller establishes the defined radiation pattern in the surface scattering antenna by activating the respective electromagnetic response of selected electromagnetic wave scattering elements. A correction circuit reduces an influence of the received possible interfering signal in a contemporaneously received signal by the associated antenna.

Antenna system facilitating reduction of interfering signals

Surface scattering antennas provide adjustable radiation fields by adjustably coupling scattering elements along a wave-propagating structure. In some approaches, the scattering elements are complementary metamaterial elements. In some approaches, the scattering elements are made adjustable by disposing an electrically adjustable material, such as a liquid crystal, in proximity to the scattering elements. Methods and systems provide control and adjustment of surface scattering antennas for various applications.

Surface scattering antennas

Described embodiments include an antenna system and method. The antenna system includes at least two surface scattering antenna segments. Each segment includes a respective electromagnetic waveguide structure, and a respective plurality of electromagnetic wave scattering elements. The wave scattering elements are distributed along the waveguide structure, have an inter-element spacing substantially less than a free-space wavelength of a highest operating frequency of the antenna segment, have a respective activatable electromagnetic response to a propagating guided wave, and are operable in combination to produce a controllable radiation pattern. A gain definition circuit defines a series of at least two radiation patterns selected to facilitate a convergence on an antenna radiation pattern that maximizes a radiation performance metric. An antenna controller sequentially establishes each radiation pattern. A receiver receives the desired field of view signal and the undesired field of view signal.

Antenna system having at least two apertures facilitating reduction of interfering signals

We have proposed a new type of the CRLH-TL consisting of two-layer planar substrates recently. It consists of a base waveguide of a substrate integrated waveguide (SIW), and series capacitances realized by slit apertures and metal patchs arranged on the upper conductor of the SIW. It is expected to become one of the basic CRLH-TL structures over 10 GHz or millimeter-wave. However radiation from the metal-patchs cannot neglect in this structure. Then we proposed a leaky-wave antenna using the SIW metal-patch type CRLH-TL. In this paper, beam scan characteristics as a function of driving frequency are confirmed theoretically and experimentally. A SIW metal-patch type CRLH-TL with transition frequency of 16 GHz is designed for a leaky-wave antenna and fabricated. Measured results agree well with theoretical and numerical results.

Backfire-to-endfire radiation characteristics of CRLH-TL using substrate integrated waveguide and metal-patches

PROBLEM TO BE SOLVED: To attain a left-handed transmission line having a planar structure which is effective even for millimeter wave with simple structure. SOLUTION: The transmission line 1 includes a main dielectric substrates 2 which is formed by laminating main ground conductor layers 4 and 5 on the opposite sides of a main dielectric layer 3. Two main ground conductor post arrays 6 each including a plurality of arrays of main ground conductor posts 7 which connect between the main ground conductor layers 4 and 5 on the opposite sides while penetrating the main dielectric layer 3 are arranged on the main dielectric substrate 2. Between the two main ground conductor post arrays 6 in the main ground conductor layer 4 on the upper side, a plurality of lines of substantially elongated slits 8 extending substantially in the width direction of the main ground conductor post array 6 are provided in the length direction of the main ground conductor post array 6. In each slit 8 of the main ground conductor layer 4 with slits, a floating conductor 9 which is isolated electrically from the main ground conductor layer 4 with slits is disposed. In the transmission line 1, the part surrounded by the main ground conductor layer 4 and the two main ground conductor post arrays 6 is constituted as a main waveguide 10. COPYRIGHT: (C)2010,JPO&INPIT

Quasi-waveguide transmission line and antenna using the same

In this paper, we suggest a method of analyzing the post-wall waveguide (PWW) or the substrate integrated waveguide (SIW) by applying the analytical technique of the H-plane waveguide discontinuities based on the planar circuit approach. The analytical procedure consists of the derivation of the mode impedance matrices for regular-shaped circuits and the short-circuiting operation on fictitious ports arranged at the peripheries of the metallic posts. First, a straight section of the PWW is treated as an example and the analytical method for the calculation of the S-parameters is described in detail. Then the attenuation and phase constants of the PWW are computed with the aid of the Thru-Reflect Line (TRL) calibration technique. Next, the analytical method is applied to the design of two types of right-angled corners. The analysis and the design results are verified using an em-simulator (HFSS).

Analysis of Post-Wall Waveguide Based on H-Plane Planar Circuit Approach

A new Composite Right/Left-Handed Transmission Line (CRLH-TL) for millimeter wave frequency is proposed and investigated theoretically and experimentally. It consists of a Substrate Integrated Waveguide (SIW) with slit apertures and a dielectric film with metal patches. A prototype of SIW Metal-patch type CRLH-TL that satisfies the balance condition is designed. Dispersion diagram and S-parameters are derived numerically, and typical field distributions of RH and LH transmission and the zero-order resonance are shown. The experimental results of the proposed SIW Metal-patch type CRLH-TL agree the analytical results well. Because both the layers of the SIW and the metal-patched dielectric film compose simple planar periodic structure, the SIW Metal-patch type CRLH-TL has advantage of simple manufacturing. It is expected to be one of the basic structure of CRLH-TL or components such as leaky wave antenna and LH coupler above 10 GHz or millimeter wave frequency.

New composite right/left-handed transmission line using substrate integrated waveguide and metal-patches

This paper describes a method to broaden the bandwidth of cruciform substrate-integrated waveguide couplers. The design and the analysis of the couplers are performed using the H-plane planar circuit approach, and the frequency characteristics of the couplers designed at 24 GHz are shown. As a result, fractional bandwidths of 30% for a 3dB coupler and 16% for a 1.7dB coupler can be realized. The design results are verified numerically and experimentally.

Kensuke Okubo

Papers

Backfire-to-endfire radiation characteristics of CRLH-TL using substrate integrated waveguide and metal-patches

Quasi-waveguide transmission line and antenna using the same

Analysis of Post-Wall Waveguide Based on H-Plane Planar Circuit Approach

New composite right/left-handed transmission line using substrate integrated waveguide and metal-patches

Broad-band cruciform substrate integrated waveguide couplers