Proposed Antenna Element Research Articles

Single-fed Ku/Ka dual-band aperture shared planar antenna array for satellite communication

This paper presents a single-fed Ku/Ka dual-band aperture-shared planar antenna array designed for satellite communication. The need to enhance data transmission speeds has driven the exploration of higher frequency bands, such as the Ku-band and Ka-band. Researchers have been investigating the design of multiband antennas to achieve space miniaturization and cost-effectiveness in these higher frequency bands. However, previous works faced challenges, including spatial efficiency limitations, complex radiator structures, band isolation issues, and increased complexity in the feeding network. To address the abovementioned challenges, this paper proposes a single-fed Ku/Ka dual-band shared-aperture planar antenna array. By combining a patch antenna for the Ku-band and a cavity antenna for the Ka-band, a simple and single-fed network is realized. The proposed antenna element is further extended to a linear array antenna and a sequentially rotated array antenna. The implemented sequentially rotated array antenna exhibited a measured impedance bandwidth of 17.4–19.7 GHz (12.4%) and 27.0–29.0 GHz (7.1%). Moreover, the proposed sequentially rotated array antenna demonstrated measured peak gains of 13.7 dBi for right-hand circular polarization in the Ku-band receiver and a measured peak gain of 15.6 dBi for left-hand circular polarization in the Ka-band transmitter, making it highly suitable for satellite communication.

Dual band notched superwideband MIMO antenna for 5G and 6G applications

In this article, a compact super wideband multiple input multiple output (MIMO) antenna with dual band elimination feature is presented. The antenna element comprises of modified square shaped radiating element and coplanar waveguide (CPW) with asymmetric ground planes. A dual-port MIMO configuration is proposed for spatial diversity. It has compact size of dimensions 18 × 37.5 × 1.6 mm3. It has frequency band of impedance matching (VSWR < 2) from 3.9– > 150 GHz (%BW > 189.86 %). The radiator and feedline are loadedwith modified M- and U-shaped slots to achieve a band notch at 5.5 GHz (WLAN) and 7.5 GHz (X-band satellite communication), respectively. A modified staircase shaped structure is used between the two ports to achieve an intraport isolation of > 20 dB at maximum frequencies. The MIMO antenna has envelope correlation coefficient based on scattering parameters < 0.005, envelope correlation coefficient based on farfield parameters < 0.08, peak gain of 8.63dBi, Mean Effective Gain (MEG) < -3dB, multiplexing efficiency > -4.0 dB, channel capacity loss (CCL) < 0.4bits/sec/Hz to signify its suitability for MIMO applications. The measured and the simulated outcomes are found to be close to each other. The proposed antenna element and MIMO antenna structure will be suitable for Internet of Things (IoT), 5G, and 6G due to their superwideband (SWB) bandwidth, desirable radiation properties and diversity performance.

Low profile cavity-embedded ultra-wideband UHF array antenna with end-fire beams

A low profile, vertically polarized, ultra-wideband array antenna with end-fire beams operating in an ultra-high frequency (UHF) band is developed in this paper. The array antenna consists of 1×16 log-periodic top-hat loaded monopole antenna arrays and is feasible to embed into a shallow cavity to further reduce the array height. Capacitance is introduced in the proposed antenna element to reduce profile height and the rectangular top hats are carefully designed to minimize the transverse dimension. Simulated results show that when the antenna array operates in a frequency range of 300 MHz–900 ​MHz, the end-fire radiation pattern achieves ±45° scanning range in the horizontal plane. Then prototypes of the proposed end-fire antenna element and a uniformly spaced linear array (1×2) are fabricated and validated. The end-fire antenna array should be suitable for airborne applications where low profile and conformal scanning phased antenna arrays with end-fire radiations are required. This design is attractive for airborne platform applications that are used to search, discover, identify, and scout the aerial target with vertically polarized beams.

A Ku‐band wideband low‐profile patch antenna with slot‐loading and parasitic structures

AbstractThis letter introduces a novel bandwidth‐enhanced low‐profile (thin structure) patch antenna adopting double U‐slot loading and parasitic structures. The proposed antenna features single‐layer topology, thin structure of 0.027 , enhanced −10 dB impedance bandwidth of 12.5%, and unidirectional radiation pattern at Ku‐band. Performances of the proposed antenna are validated through full‐wave simulations and measurements. The proposed antenna element is further duplicated to form a patch antenna array, with the parasitic structures shared by adjacent elements. The proposed antenna demonstrates potential in applications demanding wideband, highly directional radiation, and thin structure for seamless integration.

A Compact Dual-polarized Probe-fed UWB Antenna System for Breast Cancer Detection Applications

This article proposes an electrically small, probe-fed Ultra-Wideband (UWB) monopole antenna on a slotted truncated ground plane for breast cancer detection. The physical footprint of the proposed antenna element is 33 mm × 35 mm × 0.5 mm. This element is designed on the low-cost FR4 Epoxy substrate with a thickness of 0.5 mm. The proposed antenna has an electrical size of 0.33λ × 0.35λ × 0.005λ at the lowest frequency of operation; the radiator offers an impedance bandwidth of 8.34 GHz, which implies a fractional bandwidth of 115.5%. A compact dual-polarized antenna topology with two orthogonally placed probe-fed monopole antennas is proposed to achieve polarization diversity. The impedance characteristics of the individual radiating elements are maintained in spite of the electrical proximity of the radiators. The numerically computed and experimentally measured results of dual-polarized electrically small UWB antenna agree quite well. The proposed dual-polarized antenna topology is investigated for its utility in breast cancer detection in simulation.

Metamaterial Inspired Varactor-Tuned Antenna with Frequency Reconfigurability and Pattern Diversity.

A metamaterial-inspired varactor-tuned antenna with frequency reconfigurability and pattern diversity is designed. Two different versions of a reconfigurable structure are integrated into a single antenna to excite two different orthogonal patterns, which realizes pattern diversity for MIMO applications. The outer annular Composite Right-/Left-Handed Transmission Line (CRLH-TL) works at the 1 mode and provides a broadside pattern, and the inner circular radiator loaded with split ring resonators (SRR) operates at the 0 mode and radiates an omnidirectional pattern, which realizes pattern diversity. By using surface-mounted varactors, the operating frequencies for the two radiation patterns can be tuned over a wide frequency range, from 1.7 GHz to 2.2 GHz, covering the 1.71-2.17 GHz LTE band, and a low mutual coupling between the two radiators is achieved. The antenna has also been prototyped. The measured results are in good agreement with the simulation results, verifying the proposed concept. The dual-mode MIMO system equipped with the proposed antenna elements is discussed within the context of a 3-D channel model, and it shows a superior array compactness and spectral efficiency (SE) performance compared to scenarios with single-mode elements.

Triple-Band MIMO Antenna for 5 G Terminals

In this work, a triple-band, four-element antenna is designed for fifth-generation (5 G) terminals operating in LTE band 42 (3.4–3.6 GHz), LTE band 43 (3.6–3.8 GHz), and the new 5 G radio band (4.8–5.0 GHz). The proposed antenna array consists of two different types of antenna elements: a T-shaped element, which is connected to the feed line, and a C-shaped element, which is used to divide the bandwidth. The overall size of the proposed antenna element is only 10.5 mm × 5 mm. The multiantenna system has four antennas and is built on a 0.5-mm-thick Rogers 4003C substrate. The results for this antenna show a 10 dB measured bandwidth of 650 MHz at the center frequency of 3.6 GHz and 230 MHz at 4.9 GHz, a gain of more than 4 dBi, an isolation of more than 14 dB, and an overall radiation efficiency of more than 82%.

An SIW Quasi-Pyramid Horn Antenna Based on Patch Coupling Feed for Automotive Radar Sensors

An SIW quasi-pyramidal horn antenna based on patch coupling feed with reduced machining difficulty and facilitated integration with the radar chip is proposed in this paper. Compared with the metal pyramid horn antenna, the Rogers 5880 dielectric substrate based on the SIW structure is used to form the horn structure and waveguide structure, which effectively reduces the difficulty of machining the antenna. The patch coupling feed structure provides a solution for integrating the SIW quasi-pyramid horn antenna with the radar chip. The proposed SIW quasi-pyramid horn antenna element achieves approximately 9 dBi realized gain, about 95% radiation efficiency and 8.2 GHz bandwidth (74.1–82.3 GHz). A four-port inverting power divider was designed to verify the feasibility of forming an array with antenna elements. The designed antenna array achieves approximately 14.5 dBi realized gain, about 80% radiation efficiency and 7.2 GHz bandwidth (74.3–81.5 GHz). Simulation and measurement results maintain good agreement for the antenna array. To further assess the impact of errors on the performance of the proposed antenna array, we have implemented a corresponding error analysis. The proposed antenna element and antenna array show promising potential for application in automotive radar systems.

Broadband low radar cross section antennas based on H‐shaped metasurface

AbstractThis paper presents a novel metasurface antenna element and a novel metasurface antenna array, both of which have broadband low radar cross section (RCS) performance. The antenna element is constructed by two kinds of H‐shaped metasurface unit cells. One kind of H‐shaped metasurface unit cells is properly fed to radiate, and the other unit cells are used to cancel the scattering field from the former. Thus, an integration of metasurface and antenna is performed and broadband low RCS is obtained. Furthermore, a H‐shaped metasurface antenna array is also proposed by deliberately introducing metallic vias for isolation. Both the proposed antenna element and the array have almost the same radiation performance with conventional patch antennas. Numerical calculations and experimental measurements are conducted. The results verify the effectiveness of the proposed novel antennas.

A Ka-Band Silicon-Based Antenna-in-Package Design Using Characteristic Mode Analysis for Bandwidth Enhancement

With the emergence of 5G and satellite communication applications, where millimeter-wave (mm-wave) active phased arrays play an important role, the demand for a highly integrated and cost-effective method to achieve mm-wave antennas is an inevitable trend. Antenna-in-package (AiP) design is therefore becoming a hotspot. This paper presents the design procedure for a broadband silicon-based stacked patch antenna in Ka-band, which realizes a practical AiP structure for phased-array module integration requirements. A stacked-patch antenna on a high-resistivity silicon (HRSi) substrate is demonstrated to effectively extend the bandwidth with the guidance of characteristic mode analysis (CMA).The proposed antenna element and its 2 × 2 array were designed and fabricated using silicon bulk micromachining and wafer-level bonding technology. The measured results from the fabricated antenna prototypes showed that (1) the antenna element had an impedance bandwidth of 13.8% from 26.2 to 30.1 GHz, and the peak gain was 6.1 dBi at 28.9 GHz; (2) the 2 × 2 array realized an impedance bandwidth of 11.4% from 27.2 to 30.5 GHz, and the peak gain was 9.3 dBi at 28.5 GHz.

A Miniature Eight-Port Antenna Array Based on Split-Ring Resonators for 5G Sub-6 GHz Handset Applications.

In this article, a miniature eight-port multiple-input multiple-output (MIMO) antenna array is proposed for fifth-generation (5G) sub-6 GHz handset applications. The individual antenna element comprises a radiator shaped like the Chinese character "" (phonetically represented as "Wang") and three split-ring resonators (SRR) on the metal frame. The size of the individual antenna element is only 6.8 × 7 × 1 mm3 (47.6 mm3). The proposed antenna element has a -10 dB impedance bandwidth of 1.7 GHz (from 3.3 GHz to 5 GHz) that can cover 5G New Radio (NR) sub-6 GHz bands N77 (3.3-4.2 GHz), N78 (3.3-3.8 GHz), and N79 (4.4-5 GHz). The evolution design, the current distribution, the effects of single-handed holding, and the analysis of the parameters are deduced to study the approach used to design the featured antenna. The measured total efficiencies are from 40% to 80%, the isolation is better than 12 dB, the calculated envelope correlation coefficient (ECC) is less than 0.12, and the calculated channel capacity (CC) ranges from 35 to 38 bps/Hz. The presented antenna array is a good alternative to 5G mobile handsets with wideband operation, a metal frame, and minimized spacing.

Designing Eight-port Antenna Array for Multi-Band MIMO Applications in 5G Smartphones

This article introduces a dual-functional low-profile compact multiple input multiple output (MIMO) antenna array for multi-band communication in 5G smartphones. The proposed eight elements of the antenna array form two different 4×4 MIMO systems. The first four elements are placed at the four mobile corners and operate in a single band of 3.445-3.885 GHz for 5G n77 and n78 applications. The other system, in which four antennas are positioned in the middle of the terminal board, supports two wide bands of 1.684-2.300 GHz and 4.432-5.638 for n2, n3, n39, n65, n66, n79, and WLAN applications. The second iteration of a modified Peano-type fractal geometry served as the design foundation for the proposed antenna element. The system's ground plane design is based on self-isolated and spatial diversity methods. The single-band MIMO system's isolation is better than 23 dB. In the dual-band MIMO system that is based on self-isolation, isolation equals approximately 16 dB in the higher band and 10 dB in the lower band. To evaluate performance, radiation-related and total antenna efficiencies, scattering parameters and gains were investigated. Additionally, ECCs have been considered to evaluate MIMO performance. According to the results, such design constitutes a valuable option for MIMO applications in 5G smartphones.

A Parallel Folded Dipole Antenna With an Enhanced Bandwidth for 5G Millimeter-Wave Applications

In this communication, a planar folded dipole antenna array with wide operating bandwidth and compact size is proposed for 5G millimeter-wave (mmWave) applications. The basic antenna element is a pair of parallel folded dipoles (PFDs) connected at the terminals. Compared with a single half-wavelength dipole, the PFD can achieve a flatter impedance curve in the working frequency band, and it is easier to achieve broadband impedance matching with 50Ω feeding line. Moreover, a coupling slot feeding method is adopted to feed the proposed antenna element. The capacitance provided by the coupling slot can counteract the inductance caused by the PFD, thus improving the impedance matching at the low frequency band. Benefiting from the innovative design, the proposed antenna element can achieve an ultra-wide impedance bandwidth of 64% and a compact size of 0.26λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> × 0.28λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> . Furthermore, a wide scanning angle with ±50° over wide bandwidth is testified by a 1×8 array using active simulation. For verification, a 4×4 full corporate-fed array is designed based on the proposed element. The measured results prove that the proposed 4×4 array has a -10 dB impedance bandwidth of 65% covering 17 to 33.75 GHz and a peak gain of 17.5 dBi. The measured total efficiency is from 69% to 82% over the working frequency band. With the merits of compact size, wide working bandwidth, and wide beam scanning angle, the proposed antenna is a good candidate for mmWave wireless communications.

Wideband self-isolated MIMO antenna element based on multiple adjacent modes coupling current cancellation for 5G mobile terminal application

Abstract In this article, a wideband self-isolated multiple-input multiple-output (MIMO) antenna element based on multiple adjacent modes coupling current cancellation is proposed for 5G mobile terminal. The wideband self-isolated technology based on multiple adjacent mode coupling current cancellation are demonstrated. With the combination of five adjacent loop modes, the −6 dB bandwidth of the proposed self-isolated element can cover 3.3–3.8 GHz and 4.4–5.0 GHz. Finally, an 8 × 8 MIMO array is constructed by arranging eight proposed wideband self-isolated antenna elements on the two long sides of the mobile terminal. Simulated and measured results show that the isolation of 8 × 8 MIMO array exceeds 15 dB without any decoupling structures in the operating frequency band. The proposed antenna elements are simply arranged to obtain a wideband high isolation MIMO array, and it is a good choice for 5G mobile terminal.

A Low-Profile High Isolation Wideband Dual-Polarized Antenna for Sub-1 GHz Base Stations

In this paper, we present a low profile, wideband dual-polarized suspended patch antenna for LTE700/LTE850/CDMA850/GSM900 applications with high isolation. The proposed antenna element consists of two suspended patches excited orthogonally through modified cross-slot. It is theoretically and experimentally verified that this modification significantly widens −15 dB impedance bandwitdh and improves port isolation between polarizations. Experiments reveal in parallel with conducted simulations that the antenna is capable of exhibiting 37% −15 dB impedance bandwidth (688-1000 MHz) and more than 35 dB port isolation over operating frequency band. In principle planes, the antenna provides symmetric broadside radiation patterns at boresight with half-power beamwidths of 55.32º-65.61º and 61.79º-66.84º. Gain of the antenna varies within 7.3-8.4 dBi range at measured frequencies. The size of the antenna is 380 × 380 × 43.6 mm3 which makes it very suitable to integrate into commercially deployed base stations. Geometry, feeding mechanism, parametric studies and experimental results of the proposed antenna are presented throughout the paper.

Miniaturized Antenna Array-Based Novel Metamaterial Technology for Reconfigurable MIMO Systems.

In this work, a highly miniaturized microstrip antenna array based on two elements is proposed for multiple inputs multiple outputs (MIMO) application systems at sub-6 GHz frequency bands. The antenna is structured from a meander line in conjugate with an interdigital capacitor when excited through the monopole basic antenna. The proposed antenna elements are separated with a Minkowski factor-shaped metamaterial (MTM) column to achieve a separation distance (D) of 0.08λ at 3 GHz when printed on an FR-4 substrate. Later on, the antenna performance in terms of bandwidth and gain is controlled using a photonic process based on optical active switches based on light-dependent resistances (LDR). Therefore, the reconfiguration complexity with such a technique can be eliminated significantly without the need for a biasing circuit. The antenna design was conducted through several parametric studies to arrive at the optimal design that realizes the frequency bandwidth between 3 and 5.5 GHz with a maximum gain of about 4.5 dBi when all LDR terminals are off. For a wireless channel performance study-based massive MIMO environment, the proposed antenna is suitable to be configured in arrays of 64 × 64 elements. From this study, it was found the maximum bit error rate (BER) does not exceed 0.15 with a channel capacity (CC) of 2 Gbps. For validation, the antenna was fabricated based on two elements and tested experimentally. Finally, it was revealed that the measured results agree very well with simulations after comparing the theoretical calculations with the measured data.

Cost-Effective Broadband and Compact Patch Antenna Based on Ball Grid Array Packaging for 5G NR FR2 Band Applications

This brief introduces a compact, cost-effective broadband patch antenna based on ball grid array (BGA) packaging technology for 5G millimeter wave new radio (NR) FR2 band application. Based on the low-cost FR-4 substrate and single-layer configuration, the patch antenna achieves an ultra-low cost, which is attractive for large-scale 5G millimeter-wave array applications. Parasitic patches are added to the antenna to obtain broadband impedance bandwidth. To further reduce the antenna size and eliminate bulky connectors, solder balls are added to form a BGA package with connectorless interconnects. Consequently, the proposed antenna element achieves a compact size of 5.2 mm × 3.2 mm × 1.4 mm. Antenna elements and 1 × 8 array prototypes have been fabricated and verified. The measurement results show that the proposed antenna element has a -10 dB bandwidth of 56.1% (20-35.6 GHz), fully covering the 5G millimeter wave n257 (26.5-29.5 GHz), n258 (24.25-27.5 GHz), and n261 (27.5-28.35 GHz) bands. The maximum realized gains of the antenna elements and the 1 × 8 array prototype are 7.2 dBi and 13.9 dBi, respectively.

Combined Open-Slot and Monopole 8 × 8 High-Isolation Broadband MIMO Antenna System for Sub-6 GHz Terminals

In this article, an 8 × 8 MIMO antenna system with multidecoupling structures is proposed for the fifth-generation (5G) terminal applications. First, an antenna element consisting of an L-shaped open slot with dimensions of 5.6 × 5 mm2 and two bent-L-shaped monopoles with dimensions of 12.7 × 6.1 mm2 is introduced. Due to coupling feed technology, the initial open slot owns a wide bandwidth from 3.62 GHz to 4.82 GHz. For broadening the bandwidth of the initial antenna element, two bent-L-shaped monopoles are added to the open slot to adjust the input impedance. By optimizing the parameters of monopoles, the proposed antenna element has been finally determined and the bandwidth of the antenna element has been broadened (2.82 GHz to 5.23 GHz). Second, a dual antenna pair is constructed by placing the two antenna elements with an edge-to-edge distance of 27 mm in a mirror image placement; the 8 × 8 MIMO antenna system is brought about by symmetrically disposing four such antenna pairs with an edge-to-edge distance of 47 mm. Moreover, the isolation of two closely placed antenna elements is achieved by the parasitic strip-loading technique and defective ground techniques. Due to the decoupling techniques used in the 8 × 8 MIMO antenna system, the average isolation has been optimized from 13.2 dB to 21.9 dB and the total efficiency of each antenna element has been improved from a worst 20% to over 45%. Besides, the calculated mean efficiency gain is less than 1 dB, and the calculated envelop correlation coefficient (ECC) is lower than 0.01 for desired frequency bands. Furthermore, the proposed 8 × 8 MIMO antenna system has the measured broadband bandwidth from 3.28 GHz to 5.05 GHz (covering N77, N78, and N79 bands) and a compatible dimension for ultra-thin mobile phones. The simulated results of this work are all obtained from EM software CST STUDIO SUITE 2019. In general, the proposed 8 × 8 MIMO antenna system with a high-isolation property provides a hopeful solution to 5G ultra-thin mobile phones.

Microwave Imaging Approach for Breast Cancer Detection Using a Tapered Slot Antenna Loaded with Parasitic Components

In this paper, a wideband antenna is proposed for ultra-wideband microwave imaging applications. The antenna is comprised of a tapered slot ground, a rectangular slotted patch and four star-shaped parasitic components. The added slotted patch is shown to be effective in improving the bandwidth and gain. The proposed antenna system provides a realized gain of 6 dBi, an efficiency of around 80% on the radiation bandwidth, and a wide impedance bandwidth (S11 < -10 dB) of 6.3 GHz (from 3.8 to 10.1 GHz). This supports a true wideband operation. Furthermore, the fidelity factor for face-to-face (FtF) direction is 91.6%, and for side by side (SbS) is 91.2%. This proves the excellent directionality and less signal distortion of the designed antenna. These high figures establish the potential use of the proposed antenna for imaging. A heterogeneous breast phantom with dielectric characteristics identical to actual breast tissue with the presence of tumors was constructed for experimental validation. An antenna array of the proposed antenna element was situated over an artificial breast to collect reflected and transmitted waves for tumor characterization. Finally, an imaging algorithm was used to process the retrieved data to recreate the image in order to detect the undesirable tumor object inside the breast phantom.

Broadband Flexible Microstrip Antenna Array with Conformal Load-Bearing Structure.

To enhance the load-bearing mechanical properties and broadband electromagnetic characteristics of the conformal antenna, a broadband microstrip antenna array with a conformal load-bearing structure is proposed in this paper, which consists of three flexible substrate layers and two honeycomb core layers stacked on each other. By combining the antenna and honeycomb core layer in a structural perspective, the antenna array is implemented in the composition function of surface conformability and load-bearing. Additionally, the sidelobe level of the antenna is suppressed based on the reflection surface loaded. Meanwhile, an equivalent model of a honeycomb core layer has been established and applied in the design of a conformal antenna with a load-bearing structure. The presented model increases the accuracy of simulated results and reduces the memory consumption and time of the simulation. The overall size of the proposed antenna array is 32.84 × 36.65 × 4.9 mm (1.36 λ0 × 1.52 λ0 × 0.2 λ0, λ0 is the wavelength at 12.5 GHz). The proposed antenna element and array have been fabricated and measured in the flat state and under other various bending states. Experiment results show the operating relative bandwidth of the antenna array is 20.68% (11.67-13.76 GHz and 14.33-14,83 GHz) in the flat state. Under different bending conditions, the proposed antenna array covers 24.16% (11.08-14.1 GHz), 23.82% (10.63-13.5 GHz), and 23.12% with 30°, 60°, and 90° in the xoz plane (11.55-14.33 GHz). In terms of mechanical load bearing, the structure has better performance than the traditional single-layer honeycomb core load-bearing structure antenna.