Pattern Diversity Antenna Research Articles

Dual-Band Antenna with Pattern and Polarization Diversity.

This study proposes a pattern-diversity antenna with different radiation patterns at two different frequency bands (f1 and f2; f1: broadside radiation pattern, f2: conical radiation pattern). The proposed structure consists of a central circular antenna and two annular ring antennas, with each of the antennas having individual ports. Two of the ports (port 1 and port 3) exhibit orthogonal broadside radiation patterns at low bands, and the other two ports (port 1 and port 2) exhibit orthogonal conical radiation patterns at high bands. Thus, they have polarization diversity characteristics. To improve isolation between the ports, the inner part of the annular ring antennas is shorted by an array, and the outermost port is positioned orthogonal to the other ports. Using this configuration, the isolation values between the ports are -26.7 and -30.1 dB at the two frequency bands, respectively. Using the fabricated prototype, experimental results show that the proposed antenna achieves -10 dB bandwidths of 240 MHz (5.71-5.95 GHz) and 210 MHz (7.69-7.9 GHz) at f1 and f2, respectively.

On the design of ideal pattern diversity antennas with low mutual coupling using the golden angle concept

AbstractIn this paper, we come up with a unique technique to generate the ideal pattern diversity with the help of 24 Vivaldi antennas. With the help of a mathematical concept called golden angle, the 24 antenna elements are arranged in such a way that the radiation patterns will never overlap and the mutual coupling will be very low. It is also verified from the simulations and the measured results that the envelope correlation coefficient is less than 0.01 in the 3–4.2 GHz which is a sub‐6 GHz band for 5G. This same concept can be extended to a greater number of antennas also.

Pattern Diversity Antenna with Odd and Even Modes for Intelligent Wi-Fi Applications

Pattern Diversity Antenna with Odd and Even Modes for Intelligent Wi-Fi Applications

A Dual-port Pattern Diversity Antenna Based on FHMSIW Technology for Omnidirectional Coverage

A Dual-port Pattern Diversity Antenna Based on FHMSIW Technology for Omnidirectional Coverage

Pattern Diversity Antenna for 5G-NR Application Based on Closely-Spaced Semi-Circular Slots

Pattern Diversity Antenna for 5G-NR Application Based on Closely-Spaced Semi-Circular Slots

Reducing the Number of Measurement Nodes in RF Imaging Using Antenna-Pattern Diversity With an Extended Rytov Approximation

Reducing the Number of Measurement Nodes in RF Imaging Using Antenna-Pattern Diversity With an Extended Rytov Approximation

Compact, Wideband, Dual-Band Polarization and Pattern Diversity Antenna for Vehicle Communications

A new design approach of dual-band polarization and pattern diversity antenna for vehicle communications is presented. This antenna consists of three essential parts: Monopole array, swastika-shaped gap-coupled patch, and customized L-shaped driven dipole. Firstly, the monopole array composed of four monopoles beneath the patch, is excited by dipole-induced patch mode of the swastika-shaped gap-coupled patch so as to realize bidirectional beam in the upper band. Secondly, the swastika-shaped gap-coupled patch is reused as the main radiator of the lower band to achieve wideband broadside right-handed circular polarization (RHCP) radiation, which is excited by a pair of customized parallel-lines-fed L-shaped driven dipoles. Finally, two short-circuited branches are etched in the long arm of the L-shaped driven dipole, bringing in the out-of-band suppression improvement between the lower and upper bands. In order to verify the developed design method, a dual-band antenna with different polarization and radiation properties over two bands was designed, fabricated, and tested. Measured results indicate that the developed antenna with a compact transversal size of 0.36λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> *0.36λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> radiates broadside RHCP electromagnetic wave in 3.55-4.25GHz and bidirectional vertical polarization (VP) in 5.62-6.38GHz, which covers C-band and DSRC-band, and especially serves as a promising candidate for applications in both vehicle-to-satellite (V2S) and vehicle-to-everything (V2X) communications.

A Multi-Port Pattern Diversity Antenna With High Isolation

A Multi-Port Pattern Diversity Antenna With High Isolation

A Compact Wideband Pattern Diversity Antenna for 5G-NR Applications

In this letter, a novel compact wideband antenna with broadside and conical diversity patterns is presented for fifth-generation (5G)-NR applications. The capacitive loading is implemented to enhance the port isolation and for size reduction (0.35 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> × 0.29 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> × 0.047 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> ). With an extra slot mode introduced by the coupled feeding scheme, a wide impedance bandwidth is obtained. A miniaturized broadband 180° hybrid coupler is designed to provide in-phase and out-of-phase excitations. It is composed of a quarter-wavelength parallel coupled-line and lumped <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LC</i> components. As a result, conical and broadside diversity radiation patterns are achieved. The proposed antenna is analyzed, fabricated, and measured. Good agreement is achieved between the simulated and measured results. The measured overlapped −10 dB impedance bandwidth is 20.5% (3.16–3.81 GHz). The measured in-band isolation is better than 22.7 dB and the peak value achieves 34.7 dB. The proposed pattern diversity antenna exhibits good overall performance, including compact size, wide bandwidth, high isolation, and good radiation performance. Therefore, it is suitable for space-limited 5G-NR applications.

A Compact, Broadband, Monopole-Like Endfire Antenna With Reconfigurable Patterns for 5G Applications

This communication presents a novel compact, broadband, monopole-like endfire antenna with reconfigurable radiation patterns for 5G applications. Based on the mirror principle, a half-size monopole-like endfire structure with a wideband response is firstly proposed and analyzed. By switching the ON/OFF states of p-i-n diodes embedded in the passive stub lines, the monopole-like endfire structure achieves omnidirectional and endfire beam switching. Since the structure has a stable and broadband frequency response, a novel flexible pattern diversity antenna with omnidirectional coverage and directional scanned radiation is easily implemented by loading multiple stub lines. To validate the working principle, a nine-mode pattern reconfigurable antenna with a compact size of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.31\,\,\lambda _{0}\,\,\times \,\,0.31\,\,\lambda _{0}\,\,\times \,\,0.19\,\,\lambda _{0}$ </tex-math></inline-formula> ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\lambda _{0}$ </tex-math></inline-formula> is the free space wavelength at 3.75 GHz, radiator only) is designed and fabricated. The measured overlapped −10 dB impedance bandwidth for the nine modes is from 3.30 to 4.20 GHz (>24.0%), which well covers the 5G N77/N78 band. Besides, their measured gain is greater than 4.0/5.30 dBi. The proposed antenna has the merits of a compact size, simple design, wideband, good radiation performance, and flexible multibeam switching capacity. It is a good candidate for 5G new radio and other sub-6 GHz applications.

Compact planar ultra‐wideband pattern diversity antenna

AbstractA two‐port planar ultra‐wideband (UWB) pattern diversity antenna is proposed in this letter. The design consists of an array of two rotated identical monopole antennas and two feeding ports with 0° in‐phase and 180° out‐of‐phase excitations. The single monopole antenna includes a circular patch, a rectangular truncated ground plane and a fork‐shaped feeding structure. In this antenna, a modified partial common ground plane is used to enhance the input matching, increase the isolation between antenna elements and improve the desired radiations. The measured results show an |S11| &lt; −10 dB bandwidth ranging from 2 to over 20GHz, with conical and broadside beams, high efficiency, and good isolation across the entire UWB band. Also, the proposed antenna exhibits a smaller footprint, larger bandwidth, and more straightforward design compared with the existing designs. To the best of authors’ knowledge, all these characteristics have never been presented in previously reported UWB pattern diversity antennas.

Compact Wideband Pattern Reconfigurable Antennas Inspired by End-Fire Structure for 5G Vehicular Communication

Aiming for 5G-NR vehicular applications, this paper proposes two miniaturized wideband pattern reconfigurable antennas with different pattern steering capabilities. They are inspired by an end-fire structure that could be easily mounted on cars. This newly proposed planar pattern reconfigurable end-fire structure is firstly presented and studied by current distribution and equivalent circuit analysis. By turning the ON / OFF state of the PIN diodes on the passive dipole, a planar reconfigurable antenna with one omnidirectional and two end-fire beams is implemented. Additionally, a low-profile pattern diversity antenna with a compact size of 0.311 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> × 0.244 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> × 0.106 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> is implemented by loading a reactive metasurface, its main lobe can be steered in the broadside direction (35°, 0°, and −35°). Both antennas achieve a wideband response over 3.30 to 4.20 GHz (24.0%) range and good radiation efficiency of 84.0%. They feature the advantages of a miniaturized size (low-profile), structurally simple and fabrication friendly design, wideband, good radiation efficiency (low-loss), and flexible multi-beam switching capability, which are well suited for the coming sub 6 GHz vehicular applications in different scenarios.

Compact ultra-wideband pattern diversity antenna for body-centric communications

AbstractThis paper presents a pattern diversity UWB antenna for Wireless Body Area Network (WBAN) communications. Pattern diversity antenna comprises two antenna elements with directional and omnidirectional patterns suitable for off-body and on-body communications respectively. Several broad-banding techniques such as Co-Planar waveguide, parasitic patches, and cavity resonant techniques are incorporated in microstrip antenna to achieve an ultra-wideband of 7.5 GHz (3.1 to 10.6 GHz) with a directional pattern. Monopole radiator topology is utilized to achieve a UWB frequency range of 2.6–10.6 GHz with an omnidirectional pattern. Pattern diversity is achieved using an orthogonal arrangement of the antenna elements in a compact size of 40 mm × 34 mm, maintaining the isolation &gt;20 dB between the antennas. Gain varies from 2.2 to 4.6 dBi and 2.5 to 7.5 dBi for omnidirectional and directional antenna respectively. The simulated radiation efficiency for the directional antenna and the omnidirectional antenna are 74–86% and 52–66.5% respectively. The proposed design provides a good diversity performance in the entire UWB bandwidth with ECC&lt;0.1 and a diversity gain of approximately 10 dB. SAR impact evaluated under various conditions is found to be &lt;1.6 W/Kg for 1 gram of tissue.

A thin shared radiator based ACS‐fed orthogonal pattern diversity antenna with physical tilt for mmWave 5G access points

A low profile and compact two-port antenna is proposed for mmWave 5G access point applications. Since the overall space inside a typical mmWave 5G access point is limited, a small form factor based antenna module is proposed. The two-port antenna shares a common radiator that miniaturizes the overall antenna module. The proposed antenna comprises of single-layered asymmetric coplanar strip (ACS)-fed shared radiator with wide operating bandwidth ranging from 25 to 31 GHz that accounts for fractional bandwidth of 21.4%. The two-port antenna elements are oriented at right angles to each other for obtaining orthogonal pattern diversity (OPD) thereby obtaining wide angular coverage in the E-plane. Vertical linear corrugations with varying lengths are incorporated for decreasing mutual coupling between these two antenna elements and producing a uniform high gain end-fire radiation pattern. Isolation of around 4 dB is enhanced by insertion of these vertical corrugations. The proposed antenna attains peak gain of 7.2 dBi with high pattern integrity over the entire operational frequency band. The presented OPD antenna occupies overall area of 74.75 mm2 which is minimal. Moreover, implementation of the proposed antenna inside a typical mmWave 5G access point is also demonstrated. Simulation and measured results are presented with adequate technical explanation.

MetaSense: Boosting RF Sensing Accuracy Using Dynamic Metasurface Antenna

Conventional radio-frequency (RF) sensing systems rely on either frequency diversity or spatial diversity to ensure high sensing accuracy. Such reliance introduces several practical limitations that hinder the pervasive deployment of existing solutions. To circumvent this prevalent reliance, we present MetaSense, a system that leverages antenna pattern diversity for fine-grained RF sensing. MetaSense incorporates the dynamic metasurface antenna (DMA) and the auxiliary-assisted ensemble multimask learning (AEMML) framework in its design. The DMA is a novel type of antenna that can provide a diverse set of uncorrelated radiation patterns in a low-cost and low-complexity manner. The AEMML is a quality-aware learning framework that can dynamically assess and aggregate the heterogeneous channel measurements from different antenna patterns to ensure high sensing accuracy. It also incorporates a transfer learning model that allows it to generalize to new sensing conditions with few training instances required. We prototype MetaSense and demonstrate its effectiveness on a writing motion recognition task using a custom-designed 2-D DMA. The results show that MetaSense achieves 92% to 98% accuracy in classifying ten miniature writing motions, outperforming a nontunable antenna by 20% in all scenarios. Moreover, when deployed in new sensing positions where limited training instances are available, MetaSense requires as few as five training instances per class to achieve over 90% accuracy.

Compact in‐band pattern diversity antenna for wireless applications

AbstractA compact pattern diversity patch antenna working at 5.8 GHz is proposed. The patch antenna has two ports, which are responsible for the broadside radiation and omni‐directional radiation, respectively. The broadside radiation is achieved by inserting a substrate slot‐loaded integrated waveguide (SIW) cavity at the center of the patch antenna, and the omni‐directional pattern is realized by exciting the shorted patch in‐phase from both sides of the SIW cavity. Although the two operating modes share the same radiator, but a high isolation of over 30 dB is achieved, due to the cancellation of current at the inputs. In addition, two approaches are investigated to enhance the operation bandwidths. The pattern diversity antenna is prototyped and measured, showing an impedance bandwidth of 5.69–5.92 GHz for both modes/channels, and a high inter‐channel isolation over 30 dB, making it suitable for indoor wireless communication systems.

Compact Pattern Diversity Antenna with 3-D Printed All-dielectric Superstrate for WLAN Access Points

ABSTRACT This paper presents a four-port pattern diversity antenna with a 3-D printed all-dielectric superstrate for 5.2 GHz Wireless Local Area Network (WLAN) access points. The topology of four-port coaxial-fed circular patch antennas provides a beam tilt of ±45° and ±15° with an angular coverage of ±60°. The beam tilt is obtained through this unique topology, without the need for any additional phase shifting circuits. Then, a low-cost 3-D printed dielectric superstrate is designed to enhance and equalize the gain without compromising on the beam tilt and polarization purity of the antennas. The antenna module has an impedance bandwidth of 80 MHz (5.16 GHz–5.24 GHz), covering the IEEE 802.11ac band, for a gain of 9 dBi throughout the band and across the ports. The dielectric superstrate provides a gain enhancement of 3.8 dB for antennas 1 and 4, and 5.4 dB gain enhancement for antennas 2 and 3, respectively.

A Wideband Pattern Diversity Antenna With a Low Profile Based on Metasurface

In this letter, a low-profile wideband pattern diversity antenna based on metasurface (MTS) is proposed. Initially, based on the theory of characteristic mode (TCM), the two adjacent intrinsic modes, which correspond to the broadside and conical radiation pattern, respectively, are exploited to realize a wideband pattern diversity characteristic under a low profile. Then, by analyzing the modal current distribution on the MTS, the optimal locations, orientations and relative phases of the four L-shaped feeding probes are determined to excite the above two modes. However, the in-band high-order modes (HOMs) introduced by the feeding structure will deteriorate the radiation pattern. Therefore, chamfering corners on the MTS is used to suppress the HOMs for radiation pattern improvement. Finally, by combining TCM and MTS, the modes are manipulated to achieve a pattern diversity antenna with an extremely low profile of 0.06 λ0 (the free-space wavelength at the center frequency) and an isolation of better than 38 dB, which also maintains an operating bandwidth of 20.24%. Based on these excellent performances, the proposed antenna is an attractive solution for pattern diversity applications requiring low profile, especially in unmanned aerial vehicle communications.

Design of a Metasurface Antenna With Pattern Diversity

A dual-port metasurface (MS) antenna for pattern-diversity applications is proposed. The planar MS, consisting of 4 × 4 square patches, is excited by a driven patch. A pair of differential probe feed is used to drive the patch with broadside mode, while a stepped probe feed is employed in the center of the patch to generate conical mode. The capacitive-loaded stepped probe of the center feed is able to adjust the operating frequency of the conical mode and provide the two different modes with a wide overlapped frequency range. A prototype of the antenna was fabricated and measured for demonstration. The measured overlapped bandwidth (| S 11| < −10 dB) is 11.2% ranging from 5.11 to 5.72 GHz. Within the band, the measured peak gain is 11.5 dBi for the broadside mode and 6.8 dBi for the conical mode. High isolation of greater than 32 dB between the two ports is achieved over the band. Benefiting from the gain and bandwidth improvement brought by the MS, the proposed pattern diversity antenna is attractive for many wireless communication systems.

Low-Profile Broadband Antenna With Pattern Diversity

A pattern diversity antenna with low profile and wideband operation is proposed in this letter. The topology combines a 3-D folded monopole antenna together with a differential L-plate fed patch antenna. The monopole antenna is realized by a pair of bent hexagon-shaped plates, which can provide a conical pattern in the horizontal plane. A common top hat is capacitively loaded to reduce the overall height of the monopole antenna. This hat is excited as a microstrip antenna by differential feeding plates, which achieves a broadside radiation pattern. The operating band of the proposed antenna is in the range of 1.65-2.7 GHz (48%), covering the GSM1800/1900, UMTS, and LTE2300/2500 bands. By the method of differential feeding, the coupling between the two radiation modes can be greatly reduced, which can provide a low envelope correlation coefficient (≤30 dB) and a high isolation (>30 dB) between different ports. A prototype of the antenna with dimensions 60 × 60 × 20 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> is fabricated, and the measured results are in great agreement with the simulated ones.