Fixed-frequency Beam Steering Research Articles

Fixed-Frequency Beam Steering Leaky-Wave Antenna With Integrated 2-Bit Phase Shifters

In this communication, a reconfigurable 2-bit leaky-wave antenna (LWA) is proposed for low-cost fixed-frequency beam-steering applications. The proposed antenna consists of a microstrip transmission line loaded with several branches, a series of 2-bit phase shifters, and a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1\times 8$ </tex-math></inline-formula> patch array. Each phase shifter is built by selecting the feed directions on the branch and introducing slot perturbation on the patch, thus no phase delay line is used. Only three p-i-n diodes are needed to control the 0°, 90°, 180°, and 270° states of the element. The reference phase <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\varphi _{0}$ </tex-math></inline-formula> , namely the phase of the first element, is utilized to enhance the peak gain of the array. The stopband effect of broadside beam is eliminated due to the perturbation on the patches. The prototype is tested at 3.6 GHz. The measured peak gain is 13.54 dBi, and the main beam can steer from <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$- \mathrm{48}^{\circ }$ </tex-math></inline-formula> to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$+ \mathrm{46}^{\circ }$ </tex-math></inline-formula> .

Reconfigurable SIW Antenna for Fixed Frequency Beam Scanning and 5G Applications

A novel reconfigurable slotted leaky-wave antenna (LWA) based on a substrate integrated waveguide (SIW) with a fixed-frequency beam-steering capability is presented in this paper. For improved compactness, the structure is based on a SIW technology with rectangular slots fed by associated coupling with plated-through holes (PTH).This represents a new feeding method for etched slots in SIW antennas. Each via is loaded with a pin diode on both sides frontend of the waveguide. The pin diodes are tunable by adjusting the DC bias voltage, which results in beam scanning at a fixed frequency of around 27 GHz. Thus an electronically controlled steerable SIW antenna has been designed and experimentally verified that the radiation angle varies from -33° to +33°.

Review on fixed-frequency beam steering for leaky wave antenna

This paper aims to survey the efforts of researchers in response to the novel and effective technology of control radiation pattern at a fixed frequency for leaky wave antenna (LWA), map the research landscape from the literature onto coherent taxonomy and determine the basic properties of this potential field. In addition, this paper investigates the motivation behind using beam steering in LWA and the open challenges that impede the utility of this antenna design. This paper offers valuable recommendations to improve beam steering in LWA. The review revealed the development and improvement of several techniques of beam scanning LWA. However, several areas or aspects require further attention. All the articles, regardless of their research focus, attempt to address the challenges that impede the full utility of beam scanning and offer recommendations to mitigate their drawbacks. This paper contributes to this area of research by providing a detailed review of the available options and problems to allow other researchers and participants to further develop beam scanning. The new directions for this research are also described.

Radiation Pattern-Reconfigurable Leaky-Wave Antenna for Fixed-Frequency Beam Steering Based on Substrate-Integrated Waveguide

A novel reconfigurable leaky-wave antenna (LWA) with fixed-frequency beam-steering property is presented. The proposed antenna is designed on a substrate-integrated waveguide (SIW) whose effective width can be electronically changed. There are two rows of vias designed on each side of the SIW, and the vias in the outer rows are directly connected to the ground plane and top wall of the waveguide, but the vias in the inner rows are connected to the ground plane and top wall through p-i-n diodes that work as binary switches. By setting the states of the switches in a coding way, the effective width of the SIW can be changed numerically. Then, the propagation constant and the beam direction of the LWA can be altered accordingly. A prototype of the proposed antenna is fabricated and measured to verify the design procedures. The measured results show that the main beam direction can be steered from 46° to 68° in a step of 7° at the operating frequency of 5.2 GHz, which confirms the effectiveness and practicability of this design.

Fixed-Frequency Beam Steering of Microstrip Leaky-Wave Antennas Using Binary Switches

This paper presents a novel, easy-to-fabricate and operate, single-layer leaky-wave antenna (LWA) that is capable of digitally steering its beam at fixed frequency using only two values of bias voltages, with very small gain variation and good impedance matching while scanning. Steering the beam of LWAs in steps at a fixed frequency, using binary switches, is investigated, and a new half-width microstrip LWA (HW-MLWA) is presented. The basic building block of the antenna is a reconfigurable unit cell, switchable between two states. A macrocell is created by combining several reconfigurable unit cells, and the periodic LWA is formed by cascading identical macrocells. A prototype HW-MLWA was designed, fabricated, and tested to validate the concept. To achieve fixed-frequency beam scanning, a gap capacitor in each unit cell is independently connected or disconnected using a binary switch. By changing the macrocell states, the reactance profile at the free edge of the microstrip and hence the main beam direction is changed. The prototyped antenna can scan the main beam between 31° and 60° at 6 GHz. The measured peak gain of the antenna is 12.9 dBi at 6 GHz and gain variation is only 1.2 dB.

A Fixed-Frequency Beam-Steerable Half-Mode Substrate Integrated Waveguide Leaky-Wave Antenna

A single-layer design of a half-mode substrate integrated waveguide (HMSIW) leaky-wave antenna (LWA) possessing fixed-frequency beam steering capability is presented in this communication. The antenna is loaded by series and shunt capacitive tuning elements, providing two degrees of freedom in which its dispersion characteristic can be manipulated. An antenna with a length of 3.25 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> was implemented using fixed capacitors and experimentally validated. The measurements demonstrate a beam steering range between -31 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">°</sup> and +35 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">°</sup> at 6.5 GHz. The measured antenna gain is shown to be better than 9.5 dBi with circular polarization.

Development of Fixed Frequency Beam Steering Wide Band Leaky Wave Cavity Antenna

A complete design of substrate integrated leaky wave cavity antenna for fixed frequency beam steering is presented. The antenna consists of a small rectangular metallic tapered cavity fed by hook-shaped element and covered by the substrate. The steering of the beam in the desired direction is achieved by controlling the taper of the cavity. The beam is scanned at fixed frequency by changing position of the microstrip lines on the substrate. The substrate placed on the cavity resolves the problem of input impedance mismatch. The pertinent features of the antenna are compactness, broadband, and fixed-frequency beam steering capability.