Millimeter-wave Antenna Array Research Articles

A Reconfigurable Millimeter-Wave Antenna Array With Wide-Range Continuous Beamwidth Control (WCBC) Based on Polarization-Mixing

A Reconfigurable Millimeter-Wave Antenna Array With Wide-Range Continuous Beamwidth Control (WCBC) Based on Polarization-Mixing

Millimeter-Wave Wideband Dual-Polarized Aperture-Coupled Magnetoelectric Dipole Antenna Array With High Isolation

Millimeter-Wave Wideband Dual-Polarized Aperture-Coupled Magnetoelectric Dipole Antenna Array With High Isolation

Low-Profile UWB Millimeter-Wave Antenna Array Under Triple Resonant Modes Based on PCB Technology

Low-Profile UWB Millimeter-Wave Antenna Array Under Triple Resonant Modes Based on PCB Technology

A Full-Metal Dual-Band Millimeter-Wave Antenna Array With Concomitant Multifold Orthogonal Beamforming for V2V and V2I Communications

A Full-Metal Dual-Band Millimeter-Wave Antenna Array With Concomitant Multifold Orthogonal Beamforming for V2V and V2I Communications

A millimeter-wave beamforming antenna array with mutual coupling reduction using metamaterial surface

A millimeter-wave beamforming antenna array with mutual coupling reduction using metamaterial surface

Smallest form-factor multi-stacked ceramic patch antenna on package for 5G millimeter-wave mobile applications

A new design for a 5G millimeter-wave array antenna that is only 2.8 mm wide, using multi-stacked high-temperature ceramic substrates, is proposed in this paper. The antenna is designed to meet the requirements for esthetically pleasing and ergonomic smartphone designs and efficient component installations. To overcome challenges posed by the high relative permittivity and dielectric loss tangent of the ceramic substrates, the authors use a polymer adhesion layer with an air cavity and U-shaped probe feeding structures. The resulting 1 × 5 ceramic array antenna has a −10 dB impedance bandwidth in the low-band range of 24.25–28.35 GHz and the high-band range of 37–40 GHz, which covers the 5G New Radio frequency ranges n258, n260, and n261.

Wideband Circularly Polarized Antenna Array Using Three-Layer Segmented Patches for Q-Band Application

A compact wideband circularly polarized (CP) millimeter-wave (mm-wave) antenna array using three-layer segmented patches (SEP) element is presented in this letter. To achieve miniaturization and wideband feature, three-layer SEP with four <i>L</i>-shaped branches are first designed to generate three CP modes (AR minimum points) within a compact size. With the three CP modes, a broad AR bandwidth of 31.7&#x0025; is achieved by the proposed CP element. Then, four metallic vias and an <i>L</i>-shaped feeding line are used to improve impedance matching. As a result, a wide impedance bandwidth of 33.1&#x0025; is also obtained by the proposed CP element. Based on the proposed wideband CP element, a compact 4&#x00D7;4 CP antenna array fed by a simple full-incorporate microstrip network is designed. Measured results of the array show a 3 dB AR bandwidth of 29.7&#x0025; from 30.1-40.6 GHz, an impedance bandwidth of 36.1&#x0025; from 29.15-42.0 GHz, and a peak gain of 18.2 dBic, which is well suited for Q-band satellite communications.

Bandwidth enhancement of millimeter-wave microstrip patch antenna array for 5G mobile communication networks

This paper proposed enhancing the bandwidth of a millimeter wave microstrip patch antenna (MPA) and its array for a 5G mobile communication network. The proposed antenna is designed and fabricated on a Rogers RT Duroid 5,880 substrate with a standard thickness of 0.5 mm, a relative dielectric constant of 2.2, and a tangent loss of 0.0009. With a center frequency of 28 GHz, a measured return loss of -21.37 dB, a bandwidth of 1.14 GHz, and a gain of 6.27 dBi, the proposed single element operates in the local multipoint distribution service band. The proposed antenna is designed and manufactured as an array of 1×2 and 1×4 elements. The 2-element MPA array has a measured bandwidth of 1.207 GHz and a gain of 7.76 dBi, higher than that of a single element. The 4-element MPA array achieved a measured bandwidth of 2.685 GHz and a gain of 9.87 dBi, which is higher than the 2-element and single-element arrays at 28 GHz. This demonstrates that the array of antennas improves gain and bandwidth significantly. Hence, the proposed antenna and array are suitable for 5G mobile communication networks due to their small size.

Bandwidth enhancement of millimeter-wave microstrip patch antenna array for 5G mobile communication networks

This paper proposed enhancing the bandwidth of a millimeter wave microstrip patch antenna (MPA) and its array for a 5G mobile communication network. The proposed antenna is designed and fabricated on a Rogers RT Duroid 5,880 substrate with a standard thickness of 0.5 mm, a relative dielectric constant of 2.2, and a tangent loss of 0.0009. With a center frequency of 28 GHz, a measured return loss of -21.37 dB, a bandwidth of 1.14 GHz, and a gain of 6.27 dBi, the proposed single element operates in the local multipoint distribution service band. The proposed antenna is designed and manufactured as an array of 1×2 and 1×4 elements. The 2-element MPA array has a measured bandwidth of 1.207 GHz and a gain of 7.76 dBi, higher than that of a single element. The 4-element MPA array achieved a measured bandwidth of 2.685 GHz and a gain of 9.87 dBi, which is higher than the 2-element and single-element arrays at 28 GHz. This demonstrates that the array of antennas improves gain and bandwidth significantly. Hence, the proposed antenna and array are suitable for 5G mobile communication networks due to their small size.

Millimeter-wave planar antenna array augmented with a low-cost 3D printed dielectric polarizer for sensing and internet of things (IoT) applications

A unique high gain antenna array with a 3D-printed dielectric polarizer is proposed. The packaging of the antenna array feeding structure is eliminated by aggregating the feeding network in between the antenna elements. This has a significant advantage in maintaining neat and symmetric radiation characteristics with low cross-polarization levels. The proposed structure combines two elements in one feeding point to reduce the array distribution feeding points of a 4 × 4 antenna array from 16 to 8 points. The proposed antenna array structure is extremely low in cost and can be used as either a linearly or circularly polarized one. The antenna array achieves a gain of 20 dBi/dBiC in both scenarios. The matching bandwidth is 4.1%, and the 3-dB Axial Ratio (AR) bandwidth is 6%. The antenna array uses a single substrate layer without the need for any vias. The proposed antenna array suits well various applications at 24 GHz, while maintaining high performance metrics, and low cost. The antenna array can be easily integrated with transceivers due to the use of printed microstrip line technology.

Method of spatial-temporal coding of signals in the antenna array of millimeter-wave radar

Currently, most antenna systems are built based on MIMO technology. Its main advantage compared to classical antenna arrays is the possibility of a significant reduction of the number of physical transmitting and receiving channels keeping the resolution in angular coordinates. This feature is achieved due to the fact that the transmitting or receiving array is designed to be sparse, that is, the distance between the phase centers is significantly higher than half the wavelength. The cost of simplifying the design is presence of energy losses. In addition, the presence of several transmitting signals leads to the need to separate them from each other at the receiving position. The most popular method for separating orthogonal signals in MIMO arrays is code division signal separation. To implement this method, various types of orthogonal sequences are used. The most common are the Walsh, Fourier, and pseudo-random sequences. The use of orthogonal codes leads to the arising of multiple maximums in two-dimensional spectrum of the signal reflected from the object, exactly in dimension of Doppler frequency, with regular intervals. The number of maximums corresponds to the number of orthogonal sequences. Moreover, these maximums are formed in both case when using a sequence decoder and in the absence of a decoder. This feature is explained by the fact that when the sum of signals modulated in phase by Walsh sequences is multiplied by one of these sequences, one of the signals is demodulated, and the rest receive additional phase modulation. The level of additional maximum corresponds to the level of the main maximum. As a result, the ambiguity in determining the Doppler frequency appears. The indicated problem is very actual at the present time. To solve this problem, in the present paper the method of spatial-temporal coding of signals in millimeter-wave antenna array has been considered, based on the simultaneous operation of all sparse transmitters encoded by Walsh or Fourier sequences and spatial selection of transmitting beams by receiving one. The geometry of the placement of the elements of the transmitting and receiving antenna arrays corresponds to the geometry of the elements of MIMO array. At the same time, in contrast to the classical approach of beam forming for MIMO array, when individual transmitting antennas radiate orthogonal signals, and the irradiation of the target by each of them is considered separately, in the proposed method, the target is irradiated with a beam formed for transmission due to coherent spatial addition of signals from individual sparse transmitting array elements shifted in phase in accordance with the required slope of the phase front. As a result, the directivity pattern (DP) of the transmitting and receiving antenna is formed, which is equal to the product of the DP of the transmitting and receiving arrays. In this case, the interference maxima of DP of the transmitting antenna are at the zeros of DP of the receiving antenna, and the resulting DP coincides with the DP of the virtual receiving antenna formed using the classical MIMO approach. In the course of the studies and simulations, results have been obtained that show the effectiveness of the described method in terms of Doppler frequency ambiguity elimination when encoding signals in MIMO antenna arrays of the millimeter range.

Millimeter-wave Wideband High-isolation Antenna Array Based on End-fire Magnetoelectric Dipole Antenna for 5G Applications

In this paper, a millimeter-wave (mmW) wideband high-isolation wide-angle scanning antenna is presented. The end-fire magnetoelectric (ME) dipole with wideband impedance characteristic and wide beamwidth is selected. Based on the ME dipole, a 1×4 subarray with a stripline feed network is constructed to get higher antenna efficiency. Then, four 1×4 subarrays are adopted to form a 4×4 array to realize the wide-angle scanning performance. Furthermore, to get better isolation between the subarrays, the beam is tilted on the non-scanning plane; in addition, the resonant split rings are added on the background of the subarrays. With these two measures, the isolation between the subarrays can be effectively reduced, with more than 20 dB over the entire bandwidth. Owing to the wide beamwidth of ME dipole and high isolation between the subarrays, the 4×4 array can obtain the wide-angle scanning characteristic. The final antenna covers an operating bandwidth of 19.5% (24.25-29.5 GHz) with return loss more than 10 dB, which can meet the band in the 5G standard. The beam can scan approximately ±55∘ with a realized gain reduction under 3 dB within the wide operating bandwidth. Also, the simulated radiation efficiency of the array is more than 77% over almost the entire band. The antenna will be a potential candidate to be applied in 5G applications.

Neutralized meander line patch antipodal vivaldi defected ground millimeter-wave (mm-wave) antenna array

In this work, we introduce a novel series-feed 4-element antenna array that provides wider bandwidth, improved co and cross-polarization isolation, and higher gain. To achieve these three research objectives of miniaturization, bandwidth enhancement, and co-cross polarization isolation improvements, we implemented three different technologies including meandering the radiator, integrating a neutralization line, and antipodal-Vivaldi defects in the ground plane. By using these techniques in a step-wise manner, we were able to enhance the gain of a single-element meander line array radiator antenna by 5.7 dBi and suppress cross-polarization by 7.2 dB at the main lobe. The proposed 4-element antenna array has an overall size of 3.867λg×3.867λg×0.052λg. The antenna provides a measured bandwidth of 9%, covering the 27.2 GHz to 30 GHz band, with a Half-power Beamwidth (HPBW) of 33∘ and a peak measured gain of 11.426 dBi. The main lobe is located at 35∘. We conducted a precise analysis and detailed discussion of the impact of various design parameters. The presented analysis and design were validated through prototyping and testing.

A Multisurrogate-Assisted Optimization Framework for SSPP-Based mmWave Array Antenna

Spoof surface plasmon polariton (SSPP) transmission lines are frequently used to excite millimeter-wave (mmWave) antenna arrays due to high field confinement and easy integration with planar structures. However, the design of the SSPP-based array antennas requires significant efforts because of multiple specifications, the high cost of electromagnetic (EM) evaluations, and a large number of design parameters. This article proposes a multisurrogate-assisted optimization framework for the efficient design of SSPP-based mmWave array antennas. The framework has three stages. In each stage, a surrogate is proposed to solve a specific task. The first stage is to find the initial values of four key design parameters using artificial neural network (ANN)-based surrogate model optimization. The second stage focuses on the optimization of sidelobe level based on another ANN surrogate model. The third stage is a beamforming-focused optimization procedure using the space mapping technique with an improved array factor formula as a surrogate. An mmWave SSPP-based array antenna with 16 circular patches at a central frequency of 28 GHz is successfully designed using the proposed framework. The antenna is also redesigned for five sets of main lobe directions and null locations at 24 GHz. All antennas are verified using full-wave EM simulations.

Design and Analysis of a High Gain Millimeter-Wave Antenna Array for Dual Purpose Applications

Design and Analysis of a High Gain Millimeter-Wave Antenna Array for Dual Purpose Applications

Broadband Dual-Polarized mm-Wave Antenna Array With Grating Structure for Mobile Devices

In this letter, a broadband dual-polarized millimeter-wave (mm-wave) antenna array for smartphone application is proposed. Different from previous designations, this array utilizes circular-shaped slot to realize a wideband dual-polarized radiation. In addition, a novel grating structure is adopted for circular slot. With the proposed structure, a better radiation performance is realized. Operating frequency of this antenna array is measured from 26 to 38 GHz, which is calculated for more than 30% of bandwidth. In its operating band, return loss of each antenna units exceeds 10 dB and isolation between V-pol and H-pol reaches more than 15 dB. In addition, total efficiency of whole antenna array exceeds −2 dB. Peak realized gain of this antenna array reaches 12.6 and 12.5 dBi for V-pol and H-pol, respectively. Hence, the proposed antenna structure can be a promising candidate for mm-wave application in smartphone.

Angle-Domain Hybrid Beamforming-Based mmWave Massive MIMO-NOMA Systems

The millimeter-wave (mmWave) large-scale antenna arrays (LSAAs) systems play a vital role in increasing the beamforming (BF) gain and acquiring highly directional propagation. Recently, non-orthogonal multiple access (NOMA) has been integrated into these systems to manage massive connectivity and achieve spectral-efficient communications. This paper focuses on angle-domain (AD) hybrid beamforming (BF) for mmWave LSAAs and NOMA systems, thanks to the low complexity, power consumption, and channel estimation overhead. However, with limited radio-frequency chains, the hybrid BF-based single-beam (SB)-NOMA scheme generating a single beam to serve the NOMA users fails to exploit the multi-user diversity due to narrow beams with LSAAs. To tackle this limitation, we design schemes offering additional degrees of freedom. More importantly, they require only the knowledge of angular information and are suitable for either linear or rectangular antenna arrays, unlike those proposed in the literature. The first scheme exploits the time-domain resources to schedule groups having high spatial interference within distinct time slots. To minimize the need for fast and precise synchronization when applying time division multiple access (TDMA) with mmWave NOMA, we leverage the multi-beam (MB)-NOMA framework. And we propose a joint SB-and MB-NOMA scheme to benefit from NOMA multi-user diversity, whatever the cell load and the users’ positions. Using the New York University channel simulator (NYUSIM), we further validate the performance of the proposed schemes compared to the solution proposed in the literature and others using fully digital BF. Specifically, the proposed TDMA-based scheme achieves a sum-rate gain of up to 83% over the TDMA-based one existing in the literature. Moreover, we verify the superiority of applying both SB-and MB-NOMA instead of only MB-NOMA.

Ultra-Wideband Millimeter-Wave Bidirectional Circularly Polarized Monopole Antenna Array Using a Sequentially Rotated Feeding Technique

In this communication, an ultrawideband millimeter-wave (mm-Wave) bidirectional circularly polarized (CP) monopole antenna array with sequential rotation feeding (SRF) technique is proposed. First, a broadband CP monopole antenna element is realized by utilizing the asymmetric ground plane, C-shaped ring, and rectangular stub structure. A microstrip to coplanar waveguide (CPW) transition structure is designed to feed the antenna element. Then, the SRF technique is adopted to further improve the axial ratio (AR) bandwidth of the 2 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times2$ </tex-math></inline-formula> CP subarray. Finally, a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4\times4$ </tex-math></inline-formula> CP array is designed to further enhance the gain for mm-Wave applications. Measured results show that the proposed <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4\times4$ </tex-math></inline-formula> CP array exhibits the −10 dB impedance bandwidth of 102.7%, 3 dB AR bandwidths of 100.7%/101.3% in the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$+\textit {z}/-\textit {z}$ </tex-math></inline-formula> -direction, and the peak gain of 15.6 dBic.

A Planar SIW-Based Mm-Wave Frequency-Scanning Slot Antenna Array With No Scan Blindness at Normal

Planar antenna reflectors are the modern design trend of both multibeam and frequency-scanning antenna arrays. The planar implementation of reflectors is typically performed using substrate-integrated waveguide (SIW) technology. A reflector’s profile can be different from the canonical one (parabolic, elliptic, hyperbolic, etc.) because of the effect of spatial dispersion of the reflection coefficient of the SIW-based surface. It should be synthesized considering the magnitude and argument of the field reflected from such a surface to maximize the efficiency of the reflection. In this article, we present a planar millimeter-wave (mm-wave) slot antenna array with SIW-based horn–reflector feeding. We analytically formulate the optimization of the SIW surface dimensions while accounting for the spatial dispersion of the reflection coefficient. We minimize the dimensions of the planar horn–reflector feeding. Finally, we demonstrate that using a dual-slot radiating element, and we can avoid the effects of scan blindness along the normal direction. A prototype has been built and a good agreement has been achieved between the measured results and the predicted results based on calculations. The prototype achieved ±17° beam scanning within 16% of the operational frequency range, with no scan blindness along the normal direction.

An Effective Method for Episphere Total Radiated Power Tests of Millimeter-Wave Antenna Arrays

A Clenshaw-Curtis-quadrature-based approach for sub-6 GHz total radiated power testing in anechoic chambers was proposed in a previous study, demonstrating superior performance to the conventional method. However, an emerging testing demand called episphere total radiated power (ETRP) presents new challenges. The angular sampling interval for ETRP measurements of millimeter-wave antenna arrays is usually very small, which dictates time-consuming measurements and invalidates the Clenshaw-Curtis-quadrature-based method. In this short paper, we research different methods for the ETRP tests and propose an effective method based on natural neighbor interpolation. By adopting the natural neighbor interpolation to the ETRP tests, higher accuracy can be achieved without increasing the measurement time (number of samples). The proposed method is experimentally verified.