Radiation Pattern Performance Research Articles

A Radiation-Pattern Reconfigurable Antenna Array for Vehicular Communications.

This paper presents a low-profile reconfigurable antenna array capable of five radiation-pattern modes for vehicular communication applications. The antenna array consists of four antenna elements, each containing four square patches. Exciting one of the square patches generates a broadside radiation. A square parasitic patch is added at the rear of the excited patch, and two square parasitic patches are placed at the front. By optimizing the design of these parasitic patches, including the treatment of center slotting and addition of shorting pins, the antenna element achieves an end-fire beam with a certain tilt angle. On this basis, a reconfigurable feeding network is designed with 1:1 and 1:4 output modes. By connecting the reconfigurable feeding network to the four antenna elements and altering the on/off states of the PIN diodes in the feeding network, a reconfigurable antenna with four end-fire beams and one omnidirectional beam in its radiation pattern is realized. Measurement results demonstrate an excellent impedance bandwidth, radiation pattern, and gain performance in all modes. The four end-fire and one omnidirectional radiation characteristics make it highly suitable for vehicular communication applications.

Metasurface loaded ceramic based MIMO antenna with improved gain and circular polarization characteristics

In this communication, the conceptualization involves the design of a multiple input multiple output (MIMO) (dual-port) ring dielectric resonator antenna and the integration of a meta-surface onto this configuration. It introduces three distinctive attributes, which characterize the novelty of the proposed design: (a) facilitates the conversion of linearly polarized waves into circularly polarized counterparts; (b) contributes to a substantial enhancement in gain in between the working band; and (c) there is notable improvement in the isolation between the antenna ports to more than 25 dB. The experimental measurements validate the simulated results of proposed design and confirms its applicability in between 2.45–3.0 GHz. Notably, a 3-dB axial ratio is created in the frequency span of 2.56–2.99 GHz, along with an impressive gain of approximately 8.3 dBi. Its consistent radiation pattern and excellent diversity performance make it suitable for WiMAX (2.6 GHz) use.

TRIPLE-BAND CIRCULAR PATCH MICROSTRIP ANTENNA FOR WIRELESS COMMUNICATION

In this article, a triple-band patch antenna using a circular patch microstrip antenna is constructed with a low-profile patch antenna using a 1.5 mm thick FR4 substrate (εr= 4.3). As mobile devices like smartphones and laptops become more common, the usage of tiny, triple-band antennas has also become more common. The objective of this research is to design a circular patch antenna with a 3–11 GHz dipole-like radiation pattern, which may be used for industrial, scientific, and medical reasons. For the suggested triple-band antenna design, the slotted radiator with six arches and the reduction of the ground plane are among the components. In addition, the standard 50 Ω RF transmission line stimulates the patch antenna; this transmission line is attached to the microstrip line by an impedance-compliant SMA connection. Data from the experiments are obtained, evaluated, and compared; to the patch's surface current distributions, gain, and radiation patterns. According to the measurements, S11 has an impedance bandwidth in the 5.5 GHz band of less than -10 dB, 6.6 GHz band, and 10.4 GHz band at all frequencies. The superb radiation pattern performance, relatively consistent gain throughout the bands, and practical bandwidths of this antenna make it a good choice for C-band and dual X-band applications.

Design and Analysis of a Six-Element UWB-X Band MIMO Antenna for High-Speed IoT, Imaging, and Radar Applications

This research article reports a six-element multiple-input-multiple-output (MIMO) antenna for high-speed IoT, imaging, and Radar applications. The single-element UWB-X band antenna is designed and fabricated with asymmetric feed to achieve wider impedance-matched bandwidth. The antenna geometry is placed in planar on the 12-side polygon. A novel decoupling structure is used along with the ground plane which provides better isolation between each antenna and the antenna occupies an area of 8086mm2. The proposed 6 × 6 MIMO antenna design achieves measured bandwidth of 2.72–14.0 GHz. Also, prototypes are fabricated and full-wave simulation with experiment has been performed where S-parameters (reflection and transmission coefficients), the maximum peak gain of 6.65dBi, radiation pattern (stable), and diversity performance including ECC < 0.045, DG > 9.990 dB, TARC < −40 dB and CCL < 0.30 b/s/Hz has been evaluated.

Design of a multi‐function global navigation satellite system and 5G cellular antenna structure for automotive applications using characteristic mode analysis

AbstractThis paper illustrates a single antenna structure that simultaneously satisfies the antenna requirement for 5G cellular and global navigation satellite systems (GNSS). The antenna has a linearly polarised omnidirectional radiation for the newly defined 5G sub‐6 GHz cellular bands in the 617–5000 MHz frequency range. In contrast, a right‐hand circular polarisation (RHCP) with a hemispherical radiation pattern at the GNSS L1 has a frequency range of 1559–1606 MHz. This multi‐function antenna would provide a simplified product design and better space utilisation, particularly suitable for flat antenna modules and automotive. The primary concept involves employing a planar inverted F antenna structure to generate radiation modes for cellular bands and incorporate U‐slot on the top plate to generate the GNSS radiation modes. The design methodology utilises the characteristic mode analysis tool to tune the desired radiation characteristic mode at the intended frequency range for each function. The antenna was fabricated, and the performance was evaluated on a 1‐m ground plane. The GNSS RHCP gain measures 5 dBc at boresight, with an axial ratio below 2 dB across the L1 bands, while the cellular gain maintains an excellent return loss and omnidirectional radiation pattern performance across the cellular bands.

Ultra-wide band antipodal Vivaldi antenna design using target detection algorithm for detection application

This work presents a technique for detecting targets between two walls using ultra-wide band (UWB) modified antipodal Vivaldi antenna (MAVA). The detection system works on principle of time domain reflectrometry (TDR) using through wall imaging (TWI). This technique utilized a vector network analyzer (VNA) to produced short and small pluses to irradiate through an antenna array system onto the wall under study. The purposed detection system operated in UWB frequency spectrum (3.1 GHz to 10.6 GHz). Furthermore, an algorithm for hidden target detection has been developed. The results of the simulation of the designed antenna revealed a significant level of penetration, demonstrating a smart advancement in detecting and imaging system, to locate hidden metallic targets with good accuracy. A signal processing technique have been employed to improve the resolution of the target image. Using computer simulation technology (CST) software, the development and optimization process of an antenna is carried out, and the parametric performance of return loss, directivity and radiation pattern is evaluated.

A novel radial network for feeding concentric ring antenna arrays

This paper presents a novel radial network for feeding concentric ring antenna arrays. The proposed feeding network consists of a radial network of 1 input to 20 outputs. Two stages are required for this planar radial network: a radial power divider of 1 to 5 and a cascade Wilkinson power divider of 1 to 4 to generate 20 outputs that feed to a concentric rings antenna array. The proposed radial network provides a feeding network having balance in magnitude and phase to be applied in antenna systems based on a concentric rings array geometry. The paper provides as an interesting contribution the full antenna system considering the proposed radial feeding network (1 to 20) and the concentric rings antenna array. Full wave electromagnetic simulations and experimental measurements are implemented to verify the performance of matching, bandwidth and radiation pattern of the full system taking the mutual coupling into account.

Stable-Sample-Level-Based Digital Predistortion for 2-D Millimeter-Wave Phased Array Steering

This letter proposes a stable-sample-level (SL)-based digital predistortion (DPD) technique for 2-D phased array with fixed-position over-the-air (OTA) feedback (FB) to overcome significant SL fluctuation when the beam is steered. It is achieved by optimizing the phase of the beamformer based on the DPD requirement, which can control the SL at a given value without affecting the main lobe of radiation pattern, relaxing the requirement of FB dynamic range. The radiation pattern and DPD performances are measured on a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4 \times 4$ </tex-math></inline-formula> phased array at 26 GHz. The measured results show that the proposed method can realize the stable SL with good DPD performance.

Palm Tree Coplanar Vivaldi Antenna Array on the Same Substrate Size: Design and Performance Evaluation

This paper aims to describe the performance of the palm tree Coplanar Vivaldi Antenna Array (CVA) that was simulated from 0.25-6.25 GHz in terms of return loss and radiation pattern. Palm Tree Coplanar Vivaldi Antenna is available in four different configurations: single-element, two-element array, four-element array, and an eight-element array. We create a feeding network and radiator patch for two, four, and eight-array antennas. The simulation results demonstrate that the single-element antenna has the best return loss performance and can cover all frequency work from 0.25-6.25 GHz. In contrast, the antenna array can only cover multiband frequency. At 3 GHz, a single-element antenna has a directivity of 8.77 dBi, a sidelobe level of -2.2 dB, and a beamwidth of 63.70. In contrast, an antenna array of 8 elements has a directivity of 15.5 dBi, a sidelobe level of -12.6 dB, and a beamwidth of 80. Using the same substrate size, by configuring the Vivaldi Coplanar antenna to be an array at a frequency of 3 GHz, the 1×8 array antenna has a 6.73dBi improvement in directivity, a 10.4 dB boost in side lobe level, and a 55.70 enhanced in beamwidth performance compared to a single element. According to the simulation findings, the radiation pattern performance of the. Palm Tree CVA is greater than a single element in the same substrate size. Good directivity, SLL, and beamwidth performance make the proposed Palm Tree CVA array suitable for integration in telecommunication, radar, or cognitive radio applications.

Investigation of Multi-Band Reconfigurable Triangular Microstrip Antenna on Magnetic YIG Substrate

Reconfigurable antennas based on magnetised ferrite substrate and electronic components present a remarkable interest for nowadays antennas. The present research contribution deals to investigate an efficient multiband tuneable triangular microstrip antenna with acceptable characteristics, able to operate from 2.6 GHz to 5.8 GHz requiring frequency and polarization agility by dual reconfigurability using a YIG (Yttrium Iron Garnet) substrate and PIN diode. Different magnetic bias fields were applied to the proposed antenna for ON and OFF states. The obtained results and analysis demonstrate the efficiency of magnetic frequency tuning and a high stability of the radiated field, the antenna bandwidth can reach 1300 MHz for ON state, and a maximum tuning range close to 550 MHz is observed. The proposed antenna design exhibits a linear polarization and stable E and H–plane radiation pattern performance at resonance frequencies over the operating bands. These characteristics make the antenna suitable for multiband wireless communications requiring frequency agility.

Derivation of a Universally Valid Array Factor of a Conformal Arrays Based on Phase Compensation and Genetic Learning Particle Swarm Optimization

In this study, we investigated the recent deterioration of the radiation pattern performance of conformal arrays, which are applied to fields such as aircraft and vehicles. We analyzed the radiation pattern of conformal arrays in the array factor stage by combining previous studies on various beam-forming techniques for conformal arrays. To efficiently calculate and utilize the radiation pattern of conformal arrays, we derived an array factor based on phase composition for nonplanar arrays of three-dimensional (3D) coordinate systems. As an amplitude tapering method for controlling the sidelobe level of the derived 3D array factor, we propose a Bernstein polynomial generalization method based on Genetic Learning Particle Swarm Optimization. The proposed 3D array factor was verified using a cavity-backed patch antenna operating at the X-band through EM simulation of conformal arrays as a single element.

Quad-Element MIMO Antenna with Enhanced Isolation for UWB Applications

This study proposes a quad-element MIMO antenna for ultra-wideband applications. Several design evolutions have been carried out in order to achieve a UWB impedance bandwidth and good positive gain across UWB frequency ranges. In MIMO antenna construction, the best-performing antenna design is used as a basic radiator element. S-parameters, gain, radiation pattern, and diversity performance findings are used to investigate dual and quad-element MIMO antenna designs with various layouts. As a result, the proposed quad-element MIMO antenna operates in the frequency range of 3.5-11.2 GHz with &gt;-20dB isolation in the majority of the operating band. The ECC and DG values are both less than 0.006 and greater than 9.9, respectively, while the MEG and CCL are within acceptable ranges. The simulated findings agree well with the measured results.

FOUR-ELEMENT MIMO ANTENNA WITH HIGH ISOLATION AND DIVERSITY PERFORMANCE FOR UWB APPLICATIONS

A four-element multiple-input multiple-output (MIMO) antenna for wireless ultra-wideband (UWB) applications is proposed in this study. The single-element antenna is derived by conducting several design evolutions. This fundamental antenna achieves an UWB impedance bandwidth with good positive gain across the operating frequency ranges. In the investigation of MIMO antennas, dual and four-element MIMO antennas with variable layouts are designed and analyzed according to their S parameters, gain, radiation pattern, and diversity performance findings. Thus, a four-element MIMO antenna operating in the frequency range of 3.5-11.2 GHz with &amp;#62; -20 dB isolation in the majority of the band is proposed. The diversity performances in terms of envelope correlation coefficient and diversity gain are less than 0.006 and greater than 9.9, respectively, while the mean effective gain (MEG) and channel capacity loss (CCL) are within acceptable ranges. The simulated findings agree well with the measured results.

Investigating the S-parameter (|S&lt;sub&gt;11&lt;/sub&gt;|) of CPW-fed antenna using four different dielectric substrate materials for RF multiband applications

&lt;abstract&gt; &lt;p&gt;This article aims to examine the |S&lt;sub&gt;11&lt;/sub&gt;| parameter of a multiband Coplanar Waveguide (CPW)-fed antenna. The proposed square-shaped antenna-1 (Ant.1) and antenna-2 (Ant. 2) are primarily composed of three ground terminal stubs: Terminal-1 (T1), Terminal-2 (T2), and Terminal-3 (T3), all of which have an inverted L-shaped radiating patch. The proposed antennas' resonance frequencies (&lt;italic&gt;f&lt;sub&gt;r&lt;/sub&gt;&lt;/italic&gt;) can be adjusted by the electrical dimension and length of the stub resonators, the dielectric constant (ε&lt;italic&gt;&lt;sub&gt;r&lt;/sub&gt;&lt;/italic&gt;) of substrate materials, and their appropriate thicknesses. It will have an impact on their return loss (|S&lt;sub&gt;11&lt;/sub&gt;|), Impedance Bandwidth (IBW), radiation pattern, and antenna performance in terms of frequency characteristics, as demonstrated in this article. The proposed structure based on Flame-Retardant fiber glass epoxy (FR4) substrate covered a wideband frequency range from 1.5 to 3.2 GHz, (IBW = 1.7 GHz) and from 3.4 to 3.65 GHz (IBW = 0.25 GHz). The total IBW is 1.95 GHz, at S&lt;sub&gt;11&lt;/sub&gt; ≤ −10 dB with three resonance frequencies of values &lt;italic&gt;f&lt;sub&gt;r1&lt;/sub&gt;&lt;/italic&gt; = 1.75, &lt;italic&gt;f&lt;sub&gt;r2&lt;/sub&gt;&lt;/italic&gt; = 2.65, and &lt;italic&gt;f&lt;sub&gt;r3&lt;/sub&gt;&lt;/italic&gt; = 3.50 GHz) for triple-band applications. The results are compared with the research work reported earlier. The proposed Ant.1 ensured, dual and triple band applications whereas the proposed Ant. 2 ensured dual, triple and quad bands applications with reasonable antennas' sizes similar to the earlier reported works. Furthermore, the impacts of various substrate materials as well as different lengths of multi-stub resonators on the operating bands and resonance frequency are thoroughly explored and analyzed for these antennas.&lt;/p&gt; &lt;/abstract&gt;

Improvement of Coplanar Vivaldi Antenna Radiation Patterns with Fractal Structure for Ultra-Wideband Applications

The need for telecommunications technology requires fast data transfer and increasing capacity. Therefore, telecommunications technology continues to be developed by creating transmitter and receiver devices that can work at Ultra-Wideband (UWB) frequencies. This study aims to design a coplanar Vivaldi antenna with a fractal structure so that the performance of the antenna radiation pattern can increase to apply UWB frequency. The conventional coplanar Vivaldi antenna, model-A, and Model-B fractal antennas are designed to see the performance of return loss values less than -10 dB, VSWR less than 2, and working frequency of 2-10 GHz. The fractal model is created with a circular repeating structure given at the edges of the antenna patch. From the simulation results, the main lobe value of the conventional Coplanar Vivaldi antenna was 5.21 dBi, the model-A fractal was 7.02 dBi, and the Model-B fractal was 7.84 dBi. The order of the best sidelobe performance at a frequency of 6 GHz is obtained for the model-A fractal of -9 dB. Beamwidth of 46 degrees and the best main lobe direction of 0 degrees is obtained for fractal model-B. By adding a fractal structure, the lobe magnitude/directivity, sidelobe level, beamwidth, and main lobe direction can be improved

Nonplanar Tiled 1-bit Transmitarray with Phase Error Compensation

A phase compensation method for 1-bit phase quantized transmitarray is discussed. Using the tiled architecture of the transmitarray, the position of each unit cell is changed along the optical axis of the transmitarray. The spatial displacement allows changing the resulting phase distribution along the transmitarray aperture. Analytical calculations were performed to demonstrate the performance of the transmitarray radiation pattern.

Mutual Coupling Evaluation and Radiation Pattern Performance for Coplanar Vivaldi Antenna Array

This study has aimed to examine the mutual coupling evaluation and the radiation pattern performance of the Coplanar Vivaldi Antenna (CVA) array. Generally, the mutual coupling evaluation is determined based on the calculation of two antenna elements in the E-plane and the mutual scattering assessment of several linear and planar array configurations. The calculation is analyzed by multiplying the radiation pattern modeling of its element and the flux pointing vector. There has been a significant difference between the simulation and the modeling results of the radiation pattern element and mutual coupling of the Coplanar Vivaldi antenna. The mutual scattering has been determined in the contour plot with different array configurations in the E and in the H-plane. Coplanar Vivaldi Antenna with Exponential Corrugated Slot (CVA-ECT) has showed a better return loss and gain performance than CVA with No Slot (CVA-NS) in the E-plane, which is different in the H-plane. With the same volume size of an array, the smaller the width of the element is, the better the performance in radiation pattern than the wider ones is. The planar array shows that at 7 GHz, the 3×2 array gains up to 13.69 dB while 2×2 CVA-NS attains 8.9 dB in the same volume.

Radiation Pattern Performance of Bow Tie Patch Antenna for Ground Penetrating Radar (GPR) Applications

This paper presents a directional bow tie patch antenna for ground penetrating radar (GPR) applications. There are four proposed designs for this paper. Three of the antenna is designed by introducing Sierpinski gasket fractal concept on bow tie patch antenna. There is some modification on this design in order to create a new different fractal design that is applicable for GPR applications. The bow tie antenna performance is studied across 1 GHz to 4 GHz. The best return loss obtained for this paper is at 3.7 GHz where all four designs have its best performance. The comparison at 3.7 GHz of these four antenna designs presented in this paper.

Multiband corrugated circular microstrip antenna for Long Term Evolution and 5G applications

Multiband corrugated circular microstrip antenna is purposed for LTE and 5G applications. The antenna is designed of 150x150x1.6 mm3 with loop feeding to reach higher bandwidth. The corrugated structure is added to advance the multiband frequency and gain performance. Variation of the structure of the Circular Microstrip Antenna (CMA) patch is analyzed. The slit, loop feeding, ring slot and corrugated slot is simulated to get the performance of return loss and radiation pattern. Impedance bandwidth in more than nine band of frequency is achieved by corrugation structure. The antenna can provides 11 dBi of directivity and can cover in the middle/high band of LTE frequency in multiband frequency.

Mutual Coupling Reduction Using Improved Dual-Layer Mushroom and E-Shaped Stub

The improved dual-layer mushroom (IDLM) and back-to-back E-shaped stubs for mutual coupling reduction between microstrip patch antennas are presented in this paper. The IDLM unit consists of one upper layer complementary split-ring resonator lattice and four lower layer lattices, whose centers are connected to the ground by a pin. The decoupling structure can prevent the surface current from one antenna port to another, so as to improve the isolation between the antennas. The proposed antenna works in the open wireless communication band of 2.45 GHz. Using the proposed decoupling structure, a low mutual coupling level ranging from −27 to −40 dB is obtained when the center distance of the adjacent patches is 0.5λ0. The total size of the decoupling antenna is 99 × 41 × 2.4 mm3 with a frequency range of 2.42–2.48 GHz for S11 &lt; −10 dB. The proposed decoupling structure can also improve the average gain and efficiency of the antenna by 0.1 dB and 5%, respectively. The antenna is studied from the aspects of isolation, return loss, current and electric field distribution, radiation pattern, and diversity performance. The designed decoupling antenna is fabricated and measured. The pattern, isolation, and return loss of the tested results show good consistence with the simulation results. The diversity gain and envelop correlation coefficient of the diversity performance show that the designed antenna can be used in MIMO or Rx/Tx systems.