Half-width Microstrip Leaky-wave Antenna Research Articles

ARIEL: Passive Beam-Scanning Antenna teRminal for Iridescent and Efficient LEO Satellite Connectivity

A novel low-cost high-gain beam-steering antenna terminal topology for global data connectivity with low-earth-orbit satellite constellations in the UHF 900 MHz ISM band is reported. It is shown how a simple printed-circuit-board half-width microstrip leaky-wave antenna (LWA) with passive frequency-beam scanning capacity provides an energy-efficient scanning method avoiding more power-demanding and expensive beam-steering techniques (such as electronic scanning, mechanical rotation, or beam switching). For that, iridescent channel-agile operation and cross-layer optimization are needed. As an example, two single-element LWAs and an LWA array are designed to scan the celestial vault with an angular elevation scanning range of 130° and using the available LoRaWAN protocol channels from 902 to 928 MHz. It is reported a scanned-beam peak gain above 9 dBi for the compact printed-circuit LWA array design with 55 cm × 27 cm aperture dimensions.

Increasing radiation power in half width microstrip leaky wave antenna by using slots technique

<p class="Default">The radiation power in the endfire is decreased while the main beam of half substrate integrated waveguide scan from broadside to endfire in a forward. The design of half-width microstrip leaky-wave antenna (HW-MLWA) has been presented in this work to increase the power radiation near endfire by using the slots technique in the radiation element. This slot leads to a decrease the cross-polarization. The proposed design comprises one element of HW-MLWA with repeated meandered square slots in the radiation element. One aspect of this antenna is generated by using a half substrate integrated waveguide with a full tapered feed line. The proposed antenna was terminated by load of 50 Ω, and feed on the other end of the antenna. Finally, the suggested design is simulated and acceptable results were found. The released gain is increased from 10.6 dBi to 12 dBi at 4.3 GHz. This design is suitable for unmanned aerial vehicle UAVs at C band application.</p>

Radiation beam scanning for leaky wave antenna by using slots

This paper provides an insight of a new, microstrip leaky wave antenna. It holds the ability to continue steer its beam at a swapping frequency. This is done with acceptable impedance matching while scanning and very little gain variation. Investigation is carried out on LWAs’ control radiation pattern in steps at a band frequency via vertical and horizontal slots. The enhancement is realized by etching horizontal and vertical slots on the radiation element. This study also presents a novel half-width microstrip leaky wave antenna (LWA). The antenna is made up of the following basic structures group’s vertical and horizontal slots. The reactance profile at the microstrip’s free edge and thus the main beam direction is changed once the control-cell states are changed. The radiation pattern direction changes by sweeping the operating frequency between 4 GHz to 6 GHz.The main beam may be directed by the antenna between 15 o and 55 o . C band achieved the measured peak gain of the antenna of 10 dBi at 4.3 GHz beam scanning range.

Enhancement of boresight radiation for leaky wave antenna array

An array of half-width microstrip leaky-wave antennas (HW-MLWAs) of two uniform elements was designed to obtain maximum boresight radiation. Achieve this, two uniform of HW-MLWAs are placed at 180◦ and fed by a probe located at the center between the elements, two uniforms of HW-MLWAs, loaded terminated by 50Ω lumped element. Two beams from two branches individual merge to form the resultant directive beam. The simulation represents the susceptibility of the proposed array of uniform HW-MLWAs to the radiation broadside direction effectively. The predict bandwidth matched of the array is 582 MHz (4.18–4.76 GHz). The direction of its main beam in boresight happens over a wide 13%, relatively (4.18-4.76 GHz) band. The proposed peak gain at the boresight direction of the array is 9.91 dBi.

Design for radiation broadside direction using half-width microstrip leaky-wave antenna array

This work presents a new design of the uniform half-width microstrip leaky-wave antenna (HW-MLWA) array to achieve high radiation in the broadside direction. Realizing the main beam radiation of one broadside is difficult for uniform MLWA. The proposed design comprises the two elements of HW-MLWA placed at 180°, and this array is fed by a single probe in the center of two elements. One element of HW-MLWA is investigated for comparison and analysis with the proposed antenna array. Two elements are generated to combine the main beams, resulting in one beam in the broadside direction with high gain and good matching impedance. Finally, the proposed antenna is fabricated and tested. A good agreement is found between simulation and measurement results. The measured impedance bandwidth is 10.75% (4.4–4.9) GHz, and the maximum measured gain at broadside is 10.02 dBi.

Novel and active technique for controlling the radiation pattern of the half-width microstrip leaky wave antenna array

A novel, half width–microstrip leaky wave antenna (HW–MLWA) array is presented in this paper. It can electronically control its beam at fixed frequency using a double gap capacitor with diodes and has good impedance matching and very small variation gain while scanning. The control radiation pattern of leaky wave antennas (LWAs) is examined in steps at a certain frequency using binary switches, and a novel HW–MLWA array is proposed. This antenna is mainly composed of two elements of HW–MLWA and seven control unit cells (CUCs). In addition, a reconfigurable CUC is created by combining two triangle patches as double–gap capacitors with two diodes as a switch to connect the patches with a ground plane. The proposed antenna is fabricated and validated. To achieve certain–frequency beam steering, a patch in each CUCs is independently disconnected or connected with the ground plane by using PIN diode switches. When the state of the patch cell is changed, the reactance profile is altered at the free edge of the microstrip that caused the direction of the main beam to change. This proposed antenna prototype can scan the main beam between +22° to +63° at 4.2 GHz, and the antenna has a measured peak gain of 12.72 dBi at 4.2 GHz.

Achieving Fixed-Frequency Beam Scanning With a Microstrip Leaky-Wave Antenna Using Double-Gap Capacitor Technique

This study presents a novel half-width microstrip leaky-wave antenna (HW-MLWA) that can electronically control the main beam at a fixed frequency by using a double-gap capacitor with diodes, resulting in good impedance matching with small variation gain while scanning. The elementary building blocks of this antenna are periodic HW-MLWA and seven control unit cells (CUCs). A reconfigurable CUC is created by combining two triangle patches as double-gap capacitor with two diodes as switches to connect the patches with the ground plane. A gap capacitor in each patch cell is independently disconnected or connected by using a PIN diode switch. The reactance profile at the free edge of the microstrip is modified when the state of the patch cell changes, which in turn shifts the main beam direction. A single-pole double-throw switch is used to achieve backward-to-forward beam scanning at a certain frequency. An HW-MLWA is designed, fabricated, and validated. The proposed antenna prototype can scan the main beam forward between +28° and +67° and backward between –27° and –66° at 4.2 GHz. The measured peak gain of the antenna is 11.12 dBi at 4.2 GHz, and the gain variation is 1.3 dB while scanning.

Electronically controlled radiation pattern leaky wave antenna array for (C band) application

This paper provides an insight of a new, leaky-wave antenna (LWA) array. It holds the ability to digitally steer its beam at a fixed frequency by utilizing only two state of bias voltage. This is done with acceptable impedance matching while scanning and very little gain variation. Investigation is carried out on LWAs’ control radiation pattern in steps at a fixed frequency via PIN diodes switches. This study also presents a novel half-width microstrip LWA (HWMLWA) array. The antenna is made up of the following basic structures: two elements and reconfigurable control cell with each being comprised of two diodes and two triangle patches. A double gap capacitor in each unit cell is independently disconnected or connected via PIN diode switch to achieve fixed-frequency control radiation pattern. The reactance profile at the microstrip’s free edge and thus the main beam direction is changed once the control-cell states are changed. The main beam may be directed by the antenna between 61o and 19o at 4.2 GHz. C band achieved the measured peak gain of the antenna of 15 dBi at 4.2 GHz beam scanning range.

Forward and Backward Beam-Scanning Tri-Band Leaky-Wave Antenna

The main limitations of uniform half-width microstrip leaky-wave antennas (HW-MLWAs), namely a single operating band and only forward beam scanning, are overcome here with an HW-MLWA loaded with periodic L-shaped slots. The antenna exhibits tri-band operation, and the main beam can be steered in the forward direction in one band, and in the backward direction in the other two bands. Its size is halved with a shorting wall. The antenna was fabricated and tested to validate the concept, and the measured and simulated results agree very well. The measured matched (10-dB return loss) bandwidths of the prototype are 22.34 $\%$ (5.05–6.32 GHz), 15.85 $\%$ (8.77–10.28 GHz), and 11.21 $\%$ (12.63–14.13 GHz) in the first, second, and third bands, respectively. The beam-scanning ranges of the prototyped antenna are 30 $^\circ$ to 64 $^\circ$ , $-\text{75}^\circ$ to $-\text{18}^\circ$ , and $-\text{19}^\circ$ to $-\text{4}^\circ$ when the frequency sweeps from 5 to 6 GHz, 8.85 to 10.5 GHz, and 13 to 14.25 GHz, respectively. The measured peak gains (within the scanning range) are 12.4, 14.3, and 14.7 dBi in the first, second, and third bands with variations of 2.5, 3.4, and 3.1 dB, respectively.

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.

Periodic U-Slot-Loaded Dual-Band Half-Width Microstrip Leaky-Wave Antennas for Forward and Backward Beam Scanning

Half-width microstrip leaky-wave antennas (HW-MLWAs) are generally single band. Here, we present a new method to achieve dual-band operation from an HW-MLWA by periodically loading the antenna with U-shaped slots. These dual-band MLWAs are able to steer the beam in forward directions in one band and in backward directions in the other band. One of the antenna designs was prototyped and tested, and excellent agreement between the predicted and measured results were observed. The measured 10-dB return loss bandwidth of the first and second bands are $19.5 \% $ (5.24–6.37 GHz) and $13.2 \% $ (7.9–9.02 GHz), respectively. The antenna can steer the main beam from $30^\circ $ to $65^\circ $ in the first band and from $-46^\circ $ to $-10^\circ$ in the second band by sweeping the frequency from 5.25 to 6.25 GHz and 7.75 to 9 GHz, respectively. The measured peak gain of the antenna is 12.2 and 14.1 dBi in the first and second bands, respectively. Although the antenna parameters are optimized for dual-band operation, the radiation properties in another higher frequency band (third band) are also explored. In the third band, the antenna beam continuously scans from backward to forward direction as frequency increases. Moreover, this U-slot loaded single-layer half-width LWA is easy to fabricate.

An Array of Half-Width Microstrip Leaky-Wave Antennas Radiating on Boresight

An array of four uniform half-width microstrip leaky-wave antennas (MLWAs) was designed and tested to obtain maximum radiation in the boresight direction. To achieve this, uniform MLWAs are placed at 90 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">°</sup> and fed by a single probe at the center. Four beams from four individual branches combine to form the resultant directive beam. The measured matched bandwidth of the array is 300 MHz (3.8-4.1 GHz). Its beam toward boresight occurs over a relatively wide 6.4% (3.8-4.05 GHz) band. The peak measured boresight gain of the array is 10.1 dBi, and its variation within the 250-MHz boresight radiation band is only 1.7 dB.

Full-Wave Analysis and Design of Circular Half-Width Microstrip Leaky-Wave Antennas

A half-width microstrip leaky-wave antenna on a circular substrate is proposed and investigated. A microstrip on a circular substrate has a broader bandwidth for free-space leaky-wave radiation than a planar microstrip. A half-width microstrip has similar radiation characteristics to a full-width microstrip, but it does not require complex feeding structures. Full-wave analysis based on the extended spectral domain approach (ESDA) is applied to analyze the propagation characteristics of the circular half-width microstrip. The ESDA accounts for field singularities near a conductor edge of finite thickness and it does not require a virtual boundary to obtain the finite extent of the analytical space. Consequently, the ESDA is more suitable for analyzing leaky-wave structures than other conventional analysis methods. Numerical calculations are performed to determine the characteristics of the leaky-wave radiation from half-width microstrips on circular and semicircular substrates. The leaky radiation elements can be efficiently designed based on these numerical results. Two practical antennas with leaky radiation elements and feeders are designed and implemented. The measured bandwidths of the free-space leaky-wave radiation indicate that these cylindrical antennas have better performances than planar ones and they are in reasonable agreement with theoretical results. The measured radiation patterns with frequency-scanning characteristics also agree well with the simulation results.

Y-Band On-Chip Dual Half-Width Leaky-Wave Antenna in a Nanoscale CMOS Process

We present a Y-band on-chip half-width leaky-wave antenna for the integrated subterahertz transceiver in a 65-nm digital CMOS process. By utilizing the traveling-wave antenna characteristic, the proposed half-width microstrip leaky-wave antenna (MLWA) structure is concurrently matched to the Rx and Tx, relieving aperture size restriction due to the chip area constraint, while obviating the need for an explicit TR switch. The proposed transceiver (TRx) dual antenna achieves more than 30 GHz of bandwidth (BW), <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$+$</tex></formula> 4.9 dBi of maximum antenna gain, and 26.3% of radiation efficiency at 245 GHz in simulation and measures <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$+$</tex></formula> 5 dBm of maximum equivalent isotropically radiated power (EIRP) with the extremely thin antenna substrate less than 6 <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$\mu$</tex> </formula> m.

The Half-Width Microstrip Leaky Wave Antenna With the Periodic Short Circuits

A half-width microstrip leaky wave antenna (LWA) with periodic short circuits is presented. The backward-to-forward beam-scanning capability is achieved by periodic construction. The proposed antenna consists of a long rectangular patch with the short circuits that are placed with a series of shorting pins between the antenna patch and the ground plane periodically. The measurement results show that the main lobe scans electronically from 144° to 41° in H-plane (y-z plane) toward endfire (+z direction) with an open stopband when the operating frequency is increased from 4.4 GHz to 8.8 GHz.

A Reconfigurable Microstrip Leaky-Wave Antenna With a Broadly Steerable Beam

A half-width microstrip leaky-wave antenna with an electronically steerable main beam is introduced. Lumped capacitors are connected between the free edge of the antenna and the ground plane through computer controlled switches, allowing the phase constant of the propagating wave to be varied. Consequently, the main beam of the antenna can be directed along any chosen direction in the longitudinal plane, at any frequency within the operating band of the antenna. By recalling stored switch combinations, the antenna may be steered at a certain frequency, or the antenna may be frequency-scanned while maintaining the beam at a fixed angle. The antenna may also be operated in a dynamic mode using a feedback system, where appropriate switch configurations are determined in real time using an efficient search algorithm. As a proof of concept, simulations are used to determine switch states to allow beam steering through nearly a full 180 degree scan range and also to keep the main beam at a fixed angle across a broad frequency spectrum.

The Periodic Half-Width Microstrip Leaky-Wave Antenna With a Backward to Forward Scanning Capability

The periodic half-width microstrip leaky wave antenna (MLWA) with a backward to forward scanning capability is presented in this paper. The proposed antenna consists of a series of half-width MLWA. The radiating periods place on the different sides of the transmission line. The radiating period works in cutoff region of the first higher order mode, the periodic construction radiates the slow wave out along the edge. The experimental results show the main lobe scans electronically and continuously from 149° to 28° in H-plane ( y-z plane) toward end fire (+ z direction) when the operating frequency increases from 4.2-.9 GHz.

Beam Steering of a Half-Width Microstrip Leaky-Wave Antenna Using Edge Loading

A technique is presented for steering the main beam of a half-width microstrip leaky-wave antenna (LWA) at fixed frequencies over the operational frequency range. By loading the free edge of the microstrip using lumped capacitors, the phase constant may be adjusted in a prescribed manner, and the beam pointed along a desired direction. The transverse resonance method is used to explore the range of capacitances needed to steer the beam through a nearly 90° range of angles for a typical antenna. Measurements of a prototype antenna are used to validate the technique.

Quasi Microstrip Leaky-Wave Antenna With a Two-Dimensional Beam-Scanning Capability

A quasi microstrip leaky-wave antenna (QMLWA) with a two-dimensional (2-D) beam-scanning capability is presented in this paper. QMLWA consists of two half-width microstrip leaky-wave antennas with a phase-shifter. This new type of microstrip leaky-wave antenna has the advantages of reducing size, 2-D beam-scanning and suppressing back lobes. The main lobe scanning in H-plane ( <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">y</i> - <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">z</i> plane) is achieved through varying the operating frequency. When the operating frequency increases from 4.4-6 GHz, the main lobe scans from 84deg to 26deg in H-plane continuously. The main lobe steers in quasi-E-plane with varying the phase difference between two half-width microstrip leaky-wave antennas. The lobe scans from 78deg to 103deg in quasi-E-plane at 5.4 GHz. The experimental results show this short QMLWA (about 2 wavelengths) leaks power effectively. The back lobe in H-plane of QMLWA is suppressed 13 dB as compared with the conventional whole width MLWA at 5.4 GHz as example. The H-plane radiation characteristics of QMLWA are mainly determined by the width <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">s</i> of half-width MLWA and the distance <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">D</i> between two half-width MLWA together. This size-reduced QMLWA is useful in the automotive radar system and air traffic control.

Two-dimensional beam-scanning microstrip leaky-wave antenna

A novel two-dimensional beam-scanning microstrip leaky-wave antenna (MLWA) is presented. The proposed antenna consists of two half-width MLWA with a phase-shifter. This new type of MLWA has the advantages of two-dimensional beam-scanning and suppressing back lobes. This reduced size MLWA is useful in automotive radar systems and air traffic control.