X-band Communication Research Articles

Gain and bandwidth enhancement using superstrate loaded 2×2 circular-array antenna for X-Band and RADAR applications

ABSTRACT This article demonstrates the fabrication, and measurements of a corporate offset-fed 2 × 2 array electromagnetically coupled patch (EMCP) circular-antenna based on the Fabry-Perot cavity principle. Single element antenna has a low gain of 6.28 dBi and is enhanced to 13.45dBi by loading the array with a superstrate. The antenna parameters −10 dB fractional bandwidth (FBW) and gain are improved by an air gap with 4-stacked circular patches and 4 stubs in the proposed design. The peak gain of the 2 × 2 array without superstrate was 8.88 dBi at 8.19 GHz, which is enhanced to 13.82 dBi at 9.55 GHz by parasitic loading and superstrate. The FBW of the proposed array antenna was enhanced by arranging four stubs between the 4-circles in the superstrate structure. The −10 dB FBW without stubs was 24.82% (7.62–9.73 GHz) and with stubs it became 38.47% (7.73–11.0 GHz). Adjustment of the height of the superstrate at 2.0 mm not only enhanced the gain and bandwidth but also advancement in the unidirectional radiation patterns. The array is prototyped is measured to validate the reflection coefficients and radiation characteristics and they found an excellent match with simulated results. The suggested array is most suitable for energy launchers in transitions, RADAR, military, satellite, X-band communications, and microwave laboratory applications.

Meander line loaded 2-port stepped impedance feed slotted MIMO antenna for C and lower X-band communication

Abstract In this communication, a wideband 2-Port Multiple-Input-Multiple-Output (MIMO) antenna of the dimension of 0.13 λ0 × 0.68 λ0 × 0.02 λ0 mm3 (λ0, measured at a lower frequency is 4.43 GHz) is investigated for the C-band and Partial X-Band Applications. The concept of defective ground is introduced to enhance the impedance bandwidth by engraving the rectangular slots. In the proposed configuration a mender line is incorporated as a decoupling network between the antenna elements to enhance the isolation (>18 dB). The quarter wavelength long stepped impedance matched transmission line is used to excite the proposed configurations. The impedance bandwidth of the proposed antenna is (4.43–9.85 GHz)/ 83%. To explore the diversity of the MIMO system the ECC < 0.04, DG > 9.8 dB, and CCL< 0.3 bps Hz−1 are reported. Excellent agreement between simulation and measured results is obtained, justifying the MIMO antenna’s applicability for wireless applications.

Development of new lead free ceramic substrate for rectangular patch antenna application in X-band communication

This work introduces the use of Bi0.5Na0.5TiO3 (BNT) ceramic material as substrates for microstrip patch antennas operating within the frequency range of 8-12 GHz. The simulated antenna was constructed using a substrate composed of a synthesized ferroelectric perovskite-based material with a thickness of t=1.02 mm. This study investigated the intricate electromagnetic properties including permittivity, permeability, dielectric loss, magnetic loss, and miniaturization factor. Characterization techniques are used to investigate the crystal structure, local vibrational properties, surface morphology, and elemental composition of the synthesized sample. The reflection loss, return loss, and radiation pattern of the split ring microstrip patch antenna with a rectangular base were calculated using CST Microwave Studio version 2019. The parametric adjustment of the synthesized sample's uniqueness was achieved by modifying its thickness for t=0.7 mm, t=0.9 mm, t=1 mm, t=1.02 mm, and t=1.04 mm.

FSS inspired two port CP MIMO antenna with enhanced gain for X-band applications

In this work, a dual-port circularly polarized (CP) Multiple Input Multiple Output (MIMO) antenna equipped with frequency selective surface (FSS) for X-band applications is designed and analyzed. The antenna system aims to enhance gain, a critical parameter like isolation radiation pattern, etc. In wireless communication systems working in the X-band frequency range. The present MIMO antenna consists of two parts that provide coverage for the whole frequency band of 7.6–11.6 GHz, specifically for X-band communication applications. As a decoupled network, the meander line architecture greatly improves isolation. The MIMO antenna's measurements include 25 × 30 × 1 mm3. To improve the antenna's peak gain even further, a FSS is placed below the present MIMO antenna at 10.5 mm. The whole volume of the FSS-inspired composite structure is 50 × 60 × 11.6 mm3. By correctly incorporating the FSS array with the antenna's structure and utilizing its frequency-selective properties, gain improvement can be attained. Without FSS, the antenna's gain is 4.8 dBi and it is enhanced by 21 % and the maximum value of gain is 15 dBi in the desired frequency spectrum. The efficiency of the proposed FSS-inspired structure is >84.2% in the operating frequency band. To evaluate the MIMO performance of the current antenna, several attributes are evaluated. On the evaluation, it is found that the present MIMO antenna has an envelope correlation coefficient (ECC) < 0.004, a diversity gain (DG) over 9.99, measured mean effective gain (MEG) below 3 dB, and CCL of less than 0.4 bits/s/Hz throughout the resonant frequency spectrum. Through modeling and experimental testing, the current MIMO antenna model is created and verified.

Meta-atom loaded circularly polarized triple band patch antenna for Wi-Fi, ISM and X-band communications

Microstrip antennas usually suffer from high losses, gain, and efficiency degradation. It is a challenging task to miniaturize the patch antenna without degrading the performance parameters. To mitigate the above problems, a microstrip patch antenna loaded with stubs and printed on the ground plane loaded with dumbbell meta-atom is presented in this paper. The proposed double dumbbell meta-atom consists of two complementary split ring resonator (CSRR) cells loaded with rectangular rings. This exhibits the Double Negative (DNG) characteristic at 2.45 GHz. The devised meta-atom possesses dimensions of 0.05λ x 0.03λ at lower giga-hertz range. The meta-atom is further analyzed in CST-Microwave Studio and the corresponding S-parameters are extracted in MATLAB using the Nicolson Ross Weir (NRW) method. The electrical model of the meta-atom is also analyzed using Agilent ADS simulator. Further, two models of the proposed antenna with FR-4 and RT/Duroid-5880 are designed and compared. The proposed patch antenna resonates at three different frequency bands i.e. 2.445 GHz with a 3-dB bandwidth of 110 MHz (2.4 GHz–2.51 GHz), at 5.85 GHz with a 3-dB bandwidth of 730 MHz (5.13 GHz–5.86 GHz), and at 8.83 GHz with a 3-dB bandwidth of 1.83 GHz (7.7 GHz–9.53 GHz). This exhibit peak gains of 2.75dBi, 3.53dBc and 4.36dBi with low cross polarization levels at the said frequencies of operation. Further, the antenna possesses circular polarization in the frequency band (5.15 GHz–5.63 GHz). This antenna is used for Wi-Fi, ISM and X-band communications. The designed prototype is fabricated and tested and bears resemblance to the simulated results.

Novel Polyimide-Based Conformal Bandpass FSS for X-band RADAR Communications

A linearly polarized wide bandpass frequency selective surface (FSS) for RADAR communication application has been presented. The proposed FSS is constructed in a single layer with a size of 0.25 λ0. This FSS utilizes a rhombus slot comprised of a head slot and a meander line to provide a single-wideband resonance. The proposed FSS operates in the X-band communication frequency range from 7.98 to 12.1 GHz (4.12 GHz) and achieves a minimum insertion loss of 0.1 dB, respectively. The designed FSS is developed on a flexible substrate with a low profile of 0.05 mm. The FSS exhibits stable angular performance in the scope of incidence angle of 60º for both TE and TM modes. An equivalent circuit model is designed to depict the desired frequency response. Furthermore, a bending analysis has been carried out to verify the conformal nature of the proposed unit cell. The prototype is fabricated and the performances are validated with experimental results.

Design and Performance Evaluation of a Compact Frequency-Reconfigurable Coplanar-Waveguide-Fed Slotted Patch Antenna for Multi-Band Wireless Communication

A miniaturized and low-profile planar antenna is a crucial part of any wireless communication system. To cover additional narrowband services and to reduce system complexity, antennas in portable devices should offer several operating bands. In this paper, we propose a coplanar-waveguide-fed (CPW-fed), flexible, and compact slotted patch frequency reconfigurable antenna with a compact size of 20 × 24 mm2. The designed antenna employs a low-cost Rogers 5880 substrate with a thickness of 0.127 mm. This choice of substrate ensures cost-effectiveness while preserving the desired performance of the antenna. The antenna radiates through five distinct frequency bands, including 5.58–6.25 GHz, 6.05–8.81 GHz, 8.79–9.7 GHz, 9.7–10.22 GHz, and 10.48–15 GHz, depending on the switch on/off condition, thereby enabling the antenna to span a broader range of frequencies for WLAN, C-UWB, sub-6 GHz, and X-band communications. The designed antenna is fabricated and tested in both the on and off states. The measured results closely match the simulated outcomes.

Highly Efficient and Multiband Metamaterial Microstrip-Based Radiating Structure Design Showing High Gain Performance for Wireless Communication Devices

High-speed wireless communication devices need antennas to operate at multiple frequencies with high gain. The need for such antennas is increasing day by day. The proposed metamaterial superstrate antenna gives a high gain and multiband performance, which is required in high-speed wireless communication devices. The designed antenna is also applicable for C- and X-band communication devices. The structure consists of a simple patch and multiple split-ring resonator metamaterials on the superstrate region. The performance optimization is achieved by adjusting the feed position, varying the height of the superstrate layer and changing the thickness of metamaterial rings. The proposed design is analyzed for 4 GHz to 12 GHz. The performance analysis regarding the reflection coefficient, directivity, gain and electric field is observed. FR4 is used as a dielectric material that makes the design low-cost. The proposed design represents a minimum reflection coefficient response of −49 dB, a bandwidth of 490 MHz, a maximum electric field of 1.29 × 104 v/m, good directivity and a broader radiation pattern. The comparison between the simulated and the measured results is incorporated in the manuscript. A comparison of the presented design with other articles is included to check the novelty of the design. The proposed method helps to target applications such as WiFi, Earth observation and microwave links.

A 5G rotated frame radiator for ultra wideband microwave communication

AbstractA 5G rotated frame radiator for multiple applications is presented in the following paper. The presented geometry is capable of radiating the large frequency band from 2.91 to 12.17 GHz, which covers the 5G-(I) sub-6 GHz band, X-band communication with high efficiency. The impedance bandwidth of the radiator is 128%, with an electrical size of 0.24 λ × 0.24 λ × 0.15 λ in lambda. The antenna is simulated with an FR4 substrate using CST Simulator. 06-stages evolution process is also investigated by simulations, and corresponding S-parameter results are presented. Antenna's design comprises a patch in a rotated square fractal-like frame fed by a microstrip line. The proposed structure also demonstrates stable radiation patterns across the operating bandwidth. The proposed radiator has a high gain of 3.8 dBi, and an efficiency of 85%, which claimed that UWB range of the designed antenna. Therefore, it is useful for 5G-(I) sub-6 GHz band, X-band applications, including mobile, radar, and satellite microwave communication.

A Compact Dual-Band Self-Diplexing MIMO Patch Antenna for ISM and X-Band Communications

A compact, dual-band, and self-diplexing MIMO patch antenna with a shared aperture is presented for Industrial scientific medical (ISM) band and X-band communications. The structure consists of two orthogonal feed lines and a rectangular slot in a square patch. The size of the FR4 substrate is 50 × 50 × 1.6 mm3. The designed structure operates at 5.8 (ISM) and 8 GHz (X-band) frequencies independently with a simulated peak gain of 5.46 and 3.59 dBi respectively. A 13 dB of isolation is obtained for the two orthogonal ports. The obtained frequency ratio range is 1.20-1.33 over the reflection bandwidth. The design structure is fabricated and validated experimentally. The compactness and promising performance in terms of low ECC (Envelope Correlation Coefficient) (<0.1), high peak gain can make the proposed antenna a choice for current wireless devices.

Gain and Bandwidth Enhancement of X-band Compact Dielectric Resonator Antenna with Defected Ground Structure

This article presents an effective technique of gain and bandwidth enhancement for the dielectric resonator antennas (DRAs). The technique incorporates defected ground structures (DGSs) in the DRAs. Two DGS-based rectangular DRAs (DGS-RDRAs) with compact dimensions (39.6 mm × 29.2 mm) are proposed for the RADAR, satellite downlink, and other X-band communications. The DGS-RDRAs are designed by engraving circular and rectangular slots in their ground planes. Two prototypes of the proposed DGS-RDRAs are fabricated and measured so as to validate them. The measured results illustrate that the DGS-RDRA with a circular slot provides an impedance bandwidth (IBW) of 51.8% (8.413–14.29 GHz). The IBW for the rectangular-slotted DGS-RDRA is 18.69% (8–9.65 GHz). The antenna gains of 4.13 and 4.05 dBi are achieved by the circular-slotted and rectangular-slotted DGS-RDRAs, respectively. Other antenna parameters such as reflection coefficient and impedance of the antenna are also analysed. The resultant parameters obtained by the proposed DGS-RDRAs are compared with the similar type of existing DRAs in the literature. The comparisons further validate the proposed DGS-RDRAs as the best suitable candidate for the X-band applications.

360° angular coverage pattern and polarization diversities wideband circularly polarized multiple input multiple output antennas

This article presents a new design of six-element prism and eight-element cubic circularly polarized multiple input multiple output (MIMO) antennas exhibiting pattern and polarization diversity characteristics. The proposed antennas have 360° angular coverage. Each element of the MIMO antenna is radiating power in a different direction; antenna-1 radiates in −30°, antenna-2 radiates in 30°, antenna-3 radiates in 60°, and antenna-4 radiates in 120°. Antenna-5 radiates in 150°, antenna-6 radiates in −150°, antenna-7 radiates in −120°, and antenna-8 radiates in −60°.The radiation pattern can be directed in a specific direction by exciting the particular antenna element. It has wideband circular polarization in X-band (8.0–11.8 GHz). The proposed MIMO antenna element consists of pairs of mirrored monopole antennas facing each other are configured in the form of the prism and cube. The chance of mutual coupling is very high in both the configuration. A hollow copper cylinder is placed inside the prism and cube to reduce the mutual coupling. The isolation between the antennas is found better than −24 dB. The impedance matching bandwidth is 3.8 GHz (8–11.8 GHz), and the 3 dB axial ratio bandwidth is 2.69 GHz (8.01–10.7 GHz). The envelope correlation coefficient is less than 0.09, and total active reflection coefficient is less than −10 dB in a wide bandwidth. High isolation and uncorrelated radiation patterns between the adjacent elements make the proposed six-element and eight-element antenna a good candidate for massive MIMO antenna systems. The size of the antenna is 38.8 × 38.8 × 23 mm3, and this compact MIMO antenna is useful for X-band communication.

A Novel Rectangular Slot Loaded Microstrip Patch Antenna

In this communication the inclined slot loaded rectangular microstrip patch antenna fed by microstripline is presented for modern communication system. The antenna is housed in a volume of 5X3X0.16cm3. The low loss tangent and commercially available modified glass epoxy substrate material is used for the fabrication of the antenna. The design concept is presented. The proposed antenna gives a maximum bandwidth of 20.78% and overall bandwidth of 44.49% with operating range of 8.28 GHz to 12 GHz. The antenna shows broadside and linear radiation characteristics with a peak gain of 7.08 dB. The experimental and simulated results are compared. This antenna may find its applications in X-band range communication systems.

Radar cross section reduction and gain enhancement of slot antenna using polarization conversion metasurface for X‐band applications

A compact metasurface loaded slot antenna with wide impedance and radar cross section (RCS) bandwidths and a high gain is reported in this communication. The proposed polarization conversion metasurface (PCMS) and its mirror image is arranged into four quadrants and placed atop the slot antenna. A 10-dB monostatic RCS reduction from 7.85 to 12.25 GHz is achieved due to the 180° phase difference of the reflected waves from the PCMS and its mirror image. The gain of the proposed structure gets enhanced by almost 3 dB compared to the radiator alone, throughout the operating band, by partially removing the PCMS just above the slot radiator. The antenna is suitable for use in stealth applications in X-band communication. The antenna structure is fabricated and measured and a good agreement is observed between the simulated and measured results.

High-Gain Compact Circularly Polarized X-Band Superstrate Antenna for CubeSat Applications

In this letter, a concept of a high-gain circularly polarized X-band antenna employing a partially reflecting surface (PRS) has been presented. In the initial antenna analysis, the influence of parasitic element size in the PRS structure on antenna radiation pattern parameters has been investigated and the optimal arrangement of the elements has been identified. The proposed antenna provides a wide bandwidth of return loss above 10 dB of 20% (8–9.8 GHz) and circular polarization (CP) in a frequency range 8.35–8.95 GHz. The final design is compact (62 × 62 × 22.2 mm) and lightweight (29.7 g), which makes it suitable for use not only in CubeSat X-band communication systems but also in drones and high-altitude pseudosatellite applications.

(Bi13Co11)Co2O40–Co3O4 nanocomposites: Synthesis, characterization and application as substrate for microstrip patch antenna

The sillenite-cobaltite nanocomposites with chemical formula (Bi13Co11)Co2O40–Co3O4 were synthetized and characterized for application as substrate in a microstrip patch antenna. To prepare the sample, the combustion method using urea as fuel was applied. The structural and vibrational characterizations were done through X-ray diffraction and infrared spectroscopy. The morphology of the sample was studied through FESEM images. The magnetization as a function of magnetic field recorded at 300 K confirmed the paramagnetic character of the sample. Electric characterization was performed from 1.0 GHz to 8.5 GHz aiming a wide frequency spectrum data, presenting steady real relative permittivity around 7, with low losses as results. A microstrip patch antenna was designed by cavity method with the nanocomposite as substrate for application in X-band communication services. Reflection coefficient measurements displayed a good agreement with simulations, achieving only 0.39% error in resonance frequency, validating the performed morphological and electrical characterizations, as antenna design. Simulated radiation pattern is also presented, with coherent results for a directive device.

High Gain Triple-Band Metamaterial-Based Antipodal Vivaldi MIMO Antenna for 5G Communications.

This paper presents a miniaturized dual-polarized Multiple Input Multiple Output (MIMO) antenna with high isolation. The antenna meets the constraints of sub-6 GHz 5G and the smartphones’ X-band communications. A vertically polarized modified antipodal Vivaldi antenna and a horizontally polarized spiral antenna are designed and integrated, and then their performance is investigated. Three frequency bands of 3.8 GHz, 5.2 GHz, and 8.0 GHz are considered, and the proposed dual-polarized antenna is studied. High isolation of greater than 20 dB is obtained after integration of metamaterial elements, and without applying any other decoupling methods. The proposed triple-band metamaterial-based antenna has 1.6 GHz bandwidth (BW) (2.9 GHz–4.5 GHz), 13.5 dBi gain, and 98% radiation efficiency at 3.8 GHz. At 5.2 GHz it provides 1.2 GHz BW, 9.5 dBi gain, and 96% radiation efficiency. At 8.0 GHz it has 1 GHz BW, 6.75 dBi gain, and 92% radiation efficiency. Four antenna elements (with eight ports) were laid out orthogonally at the four corners of a mobile printed circuit board (PCB) to be utilized as a MIMO antenna for 5G communications. The performance of the MIMO antenna is examined and reported.

Design and Analysis of Broadband Ultrathin Reflective Linear-to-Circular Polarization Converter Using Polygon-Based Anisotropic-Impedance Surface

A broadband reflective linear-to-circular polarization converter (LCPC) is designed using a polygon-based single-layer anisotropic-impedance surface on an ultrathin (thickness is 0.053λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><b>0</b></sub> , where λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><b>0</b></sub> is the wavelength corresponding to the mid operating frequency) ground-backed substrate. Using the admittance analysis of the equivalent circuit model (ECM) and extraction of the admittance through the area moment of inertia equations, simple and generalized design guidelines are presented. The proposed polarization converter produces left-handed circularly polarized (LHCP) and right-handed circularly polarized (RHCP) reflected waves, respectively, for the linearly polarized (LP) TE and TM incident waves. It offers 46% (7.62-12.16 GHz) 3 dB axial ratio bandwidth (ARBW) for normal incidences of both the TE- and TM-polarized waves. Moreover, for oblique incidences (up to 30°) of both the LP waves, the ARBW response remains quite stable. The far-field radiation characteristics, which are often not studied, are provided to show its usability as a dual-LP to dual-CP converting reflector for X-band communications. The measurement results show good agreement with the numerically simulated results.

A superstrate loaded aperture coupled dual-band circularly polarized dielectric resonator antenna for X-band communications

AbstractA superstrate loaded cylindrical dielectric resonator antenna is developed and demonstrated for dual-band circular polarization. The proposed antenna employs a microstrip-fed rotated cross-shaped slot coupling technique for exciting the dielectric resonator (DR). The design is developed in a straight forward way. Firstly, the DR is coupled with a conventional plus-shaped slot and operates in linear polarization mode at 7.4 and 11.2 GHz. Secondly, the slot is rotated by 10° to enable out-of-phase excitation and ensure circular polarization at the above-mentioned frequencies. In the third step, a square dielectric superstrate is placed above the DR which creates multiple reflection and enhance the gain up to ~8 dBi in both the frequencies without affecting other performances. The development stages are discussed in detail. The proposed design is demonstrated through prototype fabrication and characterization. This antenna can be used for X-band satellite communications.

Wideband Frequency Selective Surface Based Transmitarray Antenna at X-Band

In this paper, a wideband multilayer transmitarray antenna is designed for Ku frequency band. The unit cell is designed at 12GHz using frequency selective surface structure. Double square ring with center patch based multilayer unit cell is simulated. The effect of substrate thickness variation on transmission coefficient magnitude and phase range is discussed. The horn antenna designed at X-band will be used as feed source for transmitarray antenna. Transmitarray simulation results show wide impedance bandwidth from 10 to 13GHz. Wide gain bandwidth of 1.975GHz with peak gain of 18.96dB is achieved. The proposed transmitarray design will find applications in high gain, directional, low profile antennas for X-band communication systems.