Entire Operating Frequency Range Research Articles

Leaky wave antenna loaded complementary elements with dual-stopband suppression

In this paper, a periodic leaky wave antenna (PLWA) using complementary elements is proposed. The complementary elements of the transverse slot (horizontal magnetic current) and the monopole pairs (vertical electric current) in the substrate integrated waveguide (SIW) is employed as the radiation element, which can simultaneously suppress closed stopband β 0 p = π and open stopband (OSB) β −1 p = 0 to enhance the forward scanning of the LWA. Additionally, the gain and cross-polarization of the element are improved due to the loading of the monopole pairs. The LWA achieves forward and backward scanning from −73° to 10° when operating at the n = −1 spatial harmonic (SH), with corresponding gains of 11.5 to 15.4 dBi. When operating at the n = 0 SH, it achieves forward scanning from 58° to 72°, with corresponding gains of 5.2 to 7.5 dBi. Moreovere, due to the element and its symmetrical structure, the cross-polarization within the entire operating frequency range is less than −35 dB. The design concept is validated through processed, fabricated, and tested.

Transmission/reflection mode switchable ultra-broadband terahertz vanadium dioxide (VO2) metasurface filter for electromagnetic shielding application

In this paper, we present an ultra-broadband terahertz (THz) vanadium dioxides (VO2) metasurface (MS) filter with switchable transmission/reflection modes for electromagnetic (EM) shielding application. The MS filter is composed of a three-layer periodic composite structure, consisting of two VO2/metallic hybrid layers and a metal mesh layer, which are separated by two benzocyclobutene (BCB) dielectric layers. The transmission property of the proposed MS filter is illustrated by the numerical simulation based on the finite element method (FEM) and equivalent circuit model (ECM). When VO2 is in insulating state, the designed composite structure acts as a filter with ultra-broadband bandpass response (BPR), exhibiting that the transmission coefficient exceeds 90 % from 1.07 THz to 3.78 THz, with a relative bandwidth of 112 %. However, owing to thermal excitation, the VO2 converts from an insulating to a metallic state, the composite structure can be functioned as a filter with ultra-broadband bandstop response (BSR) with a transmission coefficient less than 6 % spanning the range of 0.1 to 4.5 THz. In addition, the physical mechanism of the designed MS filter is investigated utilizing impedance matching theory and electric field distribution analysis. Furthermore, the MS filter has good polarization insensitivity and angular stability. Finally, we quantify the shielding effectiveness (SE) in two states and evaluate the impact structural parameters of the unit-cell, resulting in a SE of more than 25 dB in reflection mode across the entire operating frequency range. Our proposed MS filter with its exquisite performance has the potential to be widely applied in EM shielding.

Four port MIMO antenna for IoT applications in public safety band and sub-6 GHz TDD 5G band

This paper proposes a Multi Input Multi Output (MIMO) antenna specifically developed for Internet of Things (IoT) Applications in Public Safety 4.9 GHz (4940–4990 MHz) band and Sub-6 GHz TDD 5G band (4800–4990 MHz). The proposed MIMO antenna consists of Koch fractal element, and it is introduced in four port configuration. HFSS is used to design, analyze, and optimize the performance parameters of the introduced MIMO antenna. To achieve optimum performance in terms of isolation, initially all two radiating elements of 1 × 2 MIMO configuration with varying orientations have been evaluated, which are positioned on top of a cost-effective FR4 substrate. Later on 2 × 2 and 1 × 4 MIMO configurations are evaluated; and 1 × 4 configuration is fabricated and tested in lab for the verification of simulated results. The MIMO antenna demonstrates resonance at 4.97 GHz, offering a bandwidth of 320 MHz (4795–5115 MHz). It exhibits excellent performance with Envelope Correlation Coefficient (EC-C) < 0.4, Diversity Gain (D-G) > 9.8, Mean Effective Gain (ME-G) < 3 dB, Total Active Refection Coefficient (TAR-C) < −14 dB, Channel Capacity Loss (CC-L) < 0.4 bits/s/Hz, and Isolation < −20 dB across the entire operating frequency range. The proposed MIMO antenna has a maximum gain of 1.2 dBi and radiation efficiency (η) of 80%. This proposed antenna offers several advantages over traditional ones, including high efficiency (η), low CC-L, and significant isolation, even without the use of special techniques to achieve isolation.

A high-gain wideband balun-LNA with multiple noise-optimized technique

This article reports a high-gain wideband low-noise amplifier (LNA) with single ended input and differential output for multi-standard wireless receiver operating in 0.2 to 7 GHz. The proposed balun-LNA is cascode structure with common-gate–common-source (CG–CS) balun load to achieve single to differential conversion. Focusing on improving the voltage gain, bandwidth and noise performance at the same time, several techniques are implemented in this balun-LNA. A current source is added shunting CG stage to relieve voltage headroom and improve gain and linearity. Wideband input matching is achieved by active shunt-shunt resistive feedback, together with the input series inductor. Moreover, feedforward and current-reuse technique are introduced to further optimize the noise performance. The proposed LNA has a measured voltage gain of 26 dB which is nearly 6 dB higher than other balun-LNA with same supply and process. Moreover, the minimum noise figure (NF) is 2.0 dB owing to multiple noise-optimized technique. The achieved input power at 1 dB gain compression point (IP1 dB) is −14 dB m at 1 GHz and input return loss (S11) is better than −10 dB across entire operating frequency range. IIP3 and IIP2 achieve −7 dBm and 25 dBm respectively, measured at 1 GHz. The power consumption is 15.5 mW at 1.2 V supply. The LNA is fabricated in 130 nm CMOS process and the active area is 0.097 mm2. The LNA achieves high voltage gain and wide operating frequency range with low NF, which can be reflected from the figure of merit (FOM) of 23.1.

Model Predictive Control With Reduced Common-Mode Voltage Based on Optimal Switching Sequences for Nested Neutral Point Clamped Inverter

This paper proposes a new model predictive control strategy with reduced common-mode voltage (CMV) based on optimal switching sequences (OSS-MPC) for a three-phase (3PH) four-level nested neutral point clamped (4L-NNPC) inverter. The proposed method controls load current, mitigates the voltage fluctuations of flying capacitors (FCs) in the entire operating frequency range, and provides a constant inverter switching frequency. In this work, the switching sequences (SSs) are configured so that the peak CMV is limited to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$V_{dc}/6$</tex-math></inline-formula> . By involving time in the optimization process, the balance of FCs voltages is realized in the entire operating frequency, especially in low-frequency operating mode. Also, the voltage fluctuations of FCs are further mitigated through a mathematical-logic technique. To implement the proposed method on the digital signal processor, the deadbeat control technique is also used to reduce the search space and thus, computation burden. The performance of the proposed method is verified in MATLAB/SIMULINK. The experimental results are carried out based on a scaled-down hardware prototype validating the theoretical claims.

A Fibonacci Series Motivated Circularly Polarized L-Band Slotted Antenna for GNSS Application

This letter proposes a co-planar waveguide-fed circularly polarized L-band antenna for GNSS Applications. The Fibonacci series inspired us to decide the physical dimensions of the radiating structure. The proposed antenna with the dimensions of 60 × 40 × 0.8 mm3 is fabricated by etching out several slots from the patch and ground plane as well. The circular polarization (CP) behavior is observed from different shaped slots in the ground plane as well as in radiating patches. The experimental and simulation results revealed good agreement over the entire operating frequency range.

A High-Frequency Planar-Configured Millimeter-Wave MIMO Antenna for Fifth-Generation NR Operations

This article presents a simple planar millimeter-wave (mm-wave) multiple input multiple output (MIMO) antenna with four closely spaced radiating elements. The antenna is intended to enhance the bandwidth for 5G new radio (NR) applications and also cover the industrial Ka-band (26.5-40 GHz), Q-band (30-50 GHz), and U-band (40-60 GHz) frequency ranges. The antenna is designed using Rogers RT/duroid 5880 substrate with a size of 25 × 26 × 1.6 mm3. The proposed antenna consists of four identical radiating elements with two of them positioned in a linear configuration facing each other, while the other two elements are placed opposite to the first two, which improves isolation between the elements. Across the entire operating frequency range (26-60 GHz), the antenna demonstrated excellent performance, including 34 GHz wide bandwidth, high isolation of &gt;25 dB, nearly omnidirectional radiation patterns, high gain of 11.1 dB with a high radiation efficiency of 94%, low envelope correlation coefficient (ECC) of 0.0068, and high diversity gain (DG) of 9.967 dB. The simulated findings exhibit a strong positive correlation with the experimental results. The proposed MIMO antenna design is a promising solution for 5G NR applications.

An ingenious MMC topology appropriate for motor drives across their entire frequency spectrum

Modular multilevel converter (MMC) modules have popped up as among the best choices for medium and high-powered uses. This paper proposes a control scheme for the entire frequency range of operation for the MMC, focusing on supplying a three-phase machine. The machine is required to be controlled in the outer as well as the inner loop. Standard field oriented control (FOC) manages the three-phase machine in the outer closed loop while the inner control has to come up against the problem of energy balancing. That is unevenly distributed and stored in the capacitance of the upper and lower arms of the converter. There are two operating methods used in the inner control loop: a low-frequency method is used for start-up and low-speed operation, and a high-frequency method is for higher speed. In low-frequency mode (LF-mode), a special control strategy has to be implemented to minimize the energy oscillation in the capacitances of the converter arms. It makes utilization of the 3-phase machine's common mode voltage (Vc) as well as internal circulatory currents to verify a symmetrical energy distribution inside this MMC arms and also to avert whatever AC currents inside the DC source.

Chiral Metasurface Enabled Circularly Polarized OAM-Generating Folded Transmitarray Antenna With High-Gain Low-Profile and Broadband Characteristics

A broadband low-profile high-gain folded transmitarray antenna (FTA) is proposed to generate orbital angular momentum (OAM) with circular polarization. A chiral metasurface is employed as the top layer with the function of reflecting anticipant circularly polarized (CP) incident waves while transmitting the orthogonal ones. The geometric phase is then introduced to achieve 360° coverage of the transmission phase without affecting the reflection one. To obtain a high-gain and compact planar source, a 2 × 2 patch antenna array, integrated with the bottom metallic ground, is selected as the feed. Two proof-of-concept prototypes for vortex beam generation are constructed and experimentally measured. Both simulated and measured results demonstrate that <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">l</i> =–1 and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">l</i> =+1 OAM mode beams can be generated from 8.7 GHz to 9.5 GHz, and the measured maximum gains for <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">l</i> =–1 and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">l</i> =+1 reach 18.1 dBi and 18.3 dBi with the corresponding peak aperture efficiencies of 6.1% and 6.4%, respectively. Meanwhile, the axial ratios (ARs) of the peak of far-field patterns are less than 3 dB over the entire operating frequency range, providing broadband CP vortex beams. The proposed high-gain low-profile broadband FTA antenna shows a promising perspective in OAM-based wireless communication.

An Improved Finite Control-Set Model Predictive Control for Nested Neutral Point Clamped Converter

This paper presents an improved model predictive control with a finite control set (IFCS-MPC) for a four-level nested neutral point clamped (4L-NNPC) inverter. Controlling flying capacitors (FCs) voltages of 4L-NNPC, especially at low output frequency, is a challenging issue. In the proposed method, the control objectives of 4L-NNPC (current, FCs voltages, and switching losses of power devices) are formulated in terms of FCS-MPC. Furthermore, a computational burden reduction technique is introduced that reduces the search space from 216 to 96 switching states for a three-phase system. In addition to the current control, the proposed control method has the ability to control FCs voltages in the entire operating frequency range and also decreases the switching losses of the converter in comparison to the alternative methods. Also, it offers a lower computational burden than conventional FCS-MPC, which is of importance in implementation of MPC. The performance of the suggested method is verified on a 4L-NNPC in MATLAB/SIMULINK. Also, the experimental results are carried out based on a scaled-down hardware prototype validating the theoretical claims.

A Simple Design of Water-based Broadband Metamaterial Absorber for THz Applications

A simple water-based broadband metamaterial absorber has been proposed for the terahertz region. The absorption bandwidth is extended based on large frequency dispersive permittivity and high relative dielectric loss of water. The simulated result indicates that the absorption of the proposed structure achieves over 90% in the frequency range from 0.6 to 10 THz at a normal incident angle. Moreover, the performance maintains high over 80% with a wide incident angle up to 60o for transverse electronic (TE) mode and over 90% up to 700 transverse magnetic (TM) mode in the entire operating frequency range. Therefore, the designed absorber has a potential candidate for broadband THz applications.

Design and fabrication of a series contact RF MEMS switch with a novel top electrode

Radio-frequency (RF) micro-electro-mechanical-system (MEMS) switches are widely used in communication devices and test instruments. In this paper, we demonstrate the structural design and optimization of a novel RF MEMS switch with a straight top electrode. The insertion loss, isolation, actuator voltage, and stress distribution of the switch are optimized and explored simultaneously by HFSS and COMSOL software, taking into account both its RF and mechanical properties. Based on the optimized results, a switch was fabricated by a micromachining process compatible with conventional IC processes. The RF performance in the DC to 18 GHz range was measured with a vector network analyzer, showing isolation of more than 21.28 dB over the entire operating frequency range. Moreover, the required actuation voltage was about 9.9 V, and the switching time was approximately 33 μs. A maximum lifetime of 109 switching cycles was obtained. Additionally, the dimension of the sample is 1.8 mm × 1.8 mm × 0.3 mm, which might find application in the current stage.

Wideband Endfire Antenna Array for Future Short-Range Communications

A broadband, unidirectional, phased array is proposed. Single antenna element of the prototyped array is a broadband windmill-like shaped antenna. Four elements of this antenna are fed by a power divider and are configured in a novel semicircular-shaped, angular-phased array. A phase difference of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\pi $</tex-math> </inline-formula> /4 was introduced by optimizing the angular path difference among four antenna elements in the array. Total 21.5% of size reduction is achieved by introducing angular-phased array in comparison with the conventional linear-phased array. The array of radius 65 mm is prototyped on the Rogers RO4232 substrate for the operating frequency range 9.35–42.89 GHz. The proposed array configuration can maintain an average gain of 8.54 dB and average radiation efficiency of 69.71% in the entire operating frequency range while exhibiting a peak gain of 11.86 dB. The presented array exhibits highly directional behavior in the endfire direction, with the 3-dB angular beamwidth in the range from 15.1 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^\circ$</tex-math> </inline-formula> to 76.7 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^\circ$</tex-math> </inline-formula> . To the best of the authors’ knowledge, any comparable state-of-art has not been reported yet in the literature that could provide such a large impedance bandwidth in sub-mmWave range. The proposed array may find its applications for future indoor and outdoor short-range communication networks.

FSS embedded high gain ‘N’ shaped miniaturized broadband antenna

This research work represents a broadband (3.3 GHz − 17.85 GHz) high gain miniaturized (16 mm × 24 mm × 1.6 mm) microstrip patch antenna. Initially multiband property is achieved through ‘N’ shaped radiating patch surface and ‘I’ shaped ground plane surface. Finally broadband property is attained through better impedance matching by modifying feeding structure with a single step matching staircase structure. The presented antenna shows large −10 dB impedance bandwidth of 14.55 GHz with a percentage bandwidth of 138 %, Bandwidth Dimension Ratio (BDR) of 2970 and a peak gain of 4.45 dBi at 9.5 GHz. By embedding FSS (Frequency Selective Surface) structure having FSS unit cell dimension of 13 mm × 13 mm × 1.6 mm with the antenna at suitable distance, antenna gain has been elevated successfully across the entire operating frequency range (3.25 GHz–17.8 GHz). FSS coupled antenna exhibits highest gain improvement of 7.5 dBi at 3.5 GHz and peak gain of 9.1 dBi at 9.3 GHz. The FSS integrated antenna structure operates with elevated gain (peak gain of 9.1 dBi at 9.3 GHz) across the entire operating frequency range (3.25 GHz–17.8 GHz). All inclusive volume of the presented FSS coupled antenna is 52 mm × 52 mm × 21.2 mm, which can be successfully utilized in high gain broadband wireless applications. The antenna patch area miniaturization is calculated as 65 % with respect to lowest frequency of operation. The proposed FSS and antenna are developed and simulated by utilizing CST Studio Suite Software and equivalent circuit of the presented antenna is simulated utilizing ADS software. Both FSS and antenna are fabricated using inexpensive FR 4 substrate (1.6 mm thick, relative dielectric constant of 4.4 and loss tangent of 0.02) and Standard Microwave Test Bench is used to validate the antenna and composite antenna structure simulation results.

Design of an E-sectoral horn based on PRGW technology for 5G applications

AbstractE-plane sectoral horn antenna based on printed ridge gap waveguide (PRGW) technology is designed for 5G applications. It is implemented on the top plate of the PRGW structure to avoid the losses and dispersion associated with conventional feeding mechanisms. The quasi-transverse electromagneticPRGW-based antenna is excited through a planar microstrip transition. First, the single horn antenna element is introduced with the microstrip feeding section. It shows an impedance bandwidth of fractional bandwidth 26% from 45.7 to 55.4 GHz with the realized gain of 12.7 dBi and radiation efficiency of 90%. In order to maximize the realized gain, a four-element linear horn array is introduced. The same impedance bandwidth is maintained with the array having a gain of 18.6 dBi from 45.7 to 55.4 GHz. The overall antenna array performance in the entire operating frequency range is stable with a radiation efficiency around 85%. Three matching sections are implemented to achieve better impedance matching. One is used to match the horn with the feeding aperture via the PRGW line. Another section is designed to match microstrip transition with PRGW ridge. Finally, two-stage quarter wavelength transformers are required to match the power divider with the array feeding network. A prototype of single-element horn antenna was fabricated to verify the concept of the design. Simulated and measured results show that the proposed antenna can operate in the frequency band of 45–55 GHz with good agreement of radiation performance. Moreover, the proposed designs are implemented and simulated using two microwave simulation tools (CST and HFSS) to verify the radiation performance, which exhibits good agreement. The design of an E-sectoral horn antenna and its array with high gain based on PRGW is demonstrated for the first time which is considered a novel issue. It can be integrated with other passive and active elements in communication systems. Thus, it can be a valuable component in 5G communication due to its high gain, compact size and ultra-wide band.

Two Types of Common-Mode Voltage Suppression in Medium Voltage Motor Speed Regulation System Based on Solid State Transformer With Dual DC Bus

Two types of common mode voltage (CMV) exist in medium-voltage motor drive system based on modular multilevel converter (MMC) type topology, that are, arms CMV (ACMV) and system CMV (SCMV). The former will produce circulating current between phases, and the latter will do harm to the motor. This article proposes a suppression scheme of CMV with a dual dc bus MMC-based solid-state transformer (DBM <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> C-SST) based drive system. The horizontal submodules (SMs) of MMC are cascaded with a quadruple-active-bridge (QAB), then a low voltage is formed. Plus the original medium voltage bus, the system is characteristic as a dual dc bus. The primary triple-active-bridge of QAB which characterized by low-impedance and synchronous-switching helps to achieve the natural suppression of the fluctuating voltage of the MMC horizontal three SMs within the entire operating frequency range under the relevant modulation strategy, thus realizing the full suppression of ACMV and low-frequency components suppression of SCMV simultaneously, and with the additional minimum method of SCMV high-frequency components, the DBM <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> C-SST can achieve zero CMV. As the SMs fluctuating voltage and CMV are decreased, the values of SMs capacitance and arms inductance can be significantly reduced.

A 0.3–4.2-GHz Frequency-Agile Phase Shifter Based on N-Path Passive Mixers Achieving Low Rms Phase/Amplitude Error

This letter proposes a 360&#x00B0; wideband frequency-agile phase shifter utilizing the N-path passive mixer as in- phase/quadrature (I/Q) generator and vector-sum. Implicit capacitor-stacking passive mixers serve as the down-conversion I/Q generator, which provides &#x007E;6-dB voltage gain. The passive mixers are driven by four-phase 25&#x0025; duty-cycle non-overlapping pluses to ensure the I/Q signals with high accuracy. To eliminate the dependence of the amplitude adjustment on high-precision digital-to-analog converters (DACs), the pre-designed trans-conductance (<inline-formula> <tex-math notation="LaTeX">$G_{m}$ </tex-math></inline-formula>) cells-based variable gain amplifier (VGA) replaces the conventional Gilbert-based VGA. A prototype phase shifter is fabricated in CMOS 65-nm technology. Measurement results show that the phase shifter has low root-mean-square (rms) gain error and phase error, respectively, less than 0.35 dB and 0.4&#x00B0; over the entire operating frequency range of 0.3&#x2013;4.2 GHz. The total power consumption is 6&#x2013;16 mW from a 1.2-V power supply, and the active chip area (excluding pads) is only 0.06 mm².

Quad element MIMO antenna for LTE/5G (sub-6 GHz) applications

A quad-element multiple-input-multiple-output (MIMO) antenna with fractional bandwidth (FBW) of 52.42% (3.35–5.73 GHz) is proposed for LTE, WLAN (4.9/5 GHz), and 5G (sub-6 GHz) applications. The bandwidth is improved by introducing a tapered feed line and rectangular stubs in the partial ground plane. The maximum isolation of the proposed MIMO antenna is 27 dB. The diversity performance characteristics of the proposed antenna are studied in terms of the envelope correlation coefficient (ECC), diversity gain (DG), mean effective gain (MEG), total active reflection coefficient (TARC), isolation between the ports, and channel capacity loss (CCL) and the values obtained are 0.003, 9.98 dB, ±3 dB, −4 dB, −10 dB, and 0.10 bits/s/Hz respectively. A model of the proposed antenna is fabricated on the FR-4 substrate having a dielectric constant of 4.4 and a loss tangent of 0.02 with an electrical dimension of 0.45λ0 × 0.45λ0. The measured results demonstrate a decent likeness to simulated ones in the entire operating frequency range.

PHASE METHODS OF GAS GENERATORS CONTROL HYDROGEN STORAGE AND SUPPLY SYSTEMS

Methods of control of technical condition of gas generators of systems of storage and supply of hydrogen based on use of their phase-frequency characteristics are considered. Methods of control of gas generators are divided into two groups depending on the mathematical models used to describe the operation of such gas generators. It is shown that when using as such a mathematical model the transfer function of the gas generator in the form of an inertial link, it is possible to implement control algorithms both by its phase-frequency characteristics and by its time constant. In the first case, the phase-frequency characteristic is measured at an a priori set frequency. In the second case, there is no such restriction. When using as a mathematical model of the gas generator the transfer function in the form of a fractional-rational function of the second order, the implementation of algorithms for its control can be carried out directly using the phase-frequency characteristics of the gas generator. With this implementation of algorithms for monitoring the technical condition of gas generators, the measurement of the values of their phase-frequency characteristics is carried out at several frequencies. This approach to the control of gas generators can increase the reliability of its results. All methods of monitoring the technical condition of gas generators of hydrogen storage and supply systems are focused on the use of tolerance criteria. The parameters of the tolerance criteria can be both the values of the time constants of gas generators of hydrogen storage and supply systems, and fixed values of the phase-frequency characteristics of such gas generators. In the latter case, control algorithms are implemented that cover the entire operating frequency range of gas generators.

Double Meander Dipole Antenna Array with Enhanced Bandwidth and Gain

In this paper, a new design of high gain and wide bandwidth microstrip patch antenna array containing double meander dipole structure is proposed. Two in-phase resonant frequencies in the Ku-band (12–18 GHz) could be achieved in the double meander dipole array structure, which lead to enhance impedance bandwidth without costing extra design section. Besides, further enhanced gain of 2 dBi of the array over the entire operating frequency range has been achieved by introducing a double-layer substrate technique. The proposed antenna has been fabricated using the E33 model LPKF prototyping PCB machine. The measurement results have been performed, and they are in very good agreement with the simulation results. The measured –10 dB impedance bandwidth indicates that the array provides a very wide bandwidth which is around 30% at the center frequency of 15.5 GHz. A stable gain with a peak value of 10 dBi is achieved over the operating frequency range. The E- and H-plane radiation patterns are simulated, and a very low sidelobe level is predicted. The proposed antenna is simple and has relatively low-profile, and it could be a good candidate for millimeter wave communications.