dB Return Loss Bandwidth Research Articles

Development of an innovative patch antenna design and implementation using ENG materials for health care systems and 5G networks

The object of this study is a new design of an overhead microstrip antenna, including Epsilon Negative (ENG) metamaterials and L-shaped parasitic overlays aimed at achieving dual-band operation and improving the performance of modern wireless communication systems. The research is aimed at solving the problem of limited bandwidth and dual-band functionality in conventional antenna designs. This study solves the problem of limited bandwidth and dual-band functionality in conventional microstrip patch antenna designs, which are crucial for modern wireless communication systems. The inclusion of L-shaped parasitic overlays effectively expands the bandwidth in each frequency range. The results indicate significant improvements: at the upper resonant frequency, a 10 dB return loss bandwidth of 27.84 % (2.88–3.81 GHz) and a 3 dB axial ratio bandwidth of 5.05 % (2.90–3.05 GHz) are achieved, while at the lower resonant frequency, a return loss bandwidth is 10 dB, which is 6.11 % (2.22–2.36 GHz). These improvements indicate a significant increase in antenna performance compared to conventional designs, which is confirmed by comparing the simulation results with the measurement results. Distinctive features contributing to these results include the use of ENG metamaterials, which improve electromagnetic properties and signal propagation; vertical transitions, which provide efficient dual-band operation; and L-shaped parasitic overlays, which significantly expand bandwidth. These characteristics combine to eliminate the limitations of traditional designs, which makes the proposed antenna suitable for use in a wide frequency range in modern wireless communication systems.

A simulation study of dual band THz soft antenna for biomedical applications

The demand for multiband and high-gain THz antennas is escalating due to advancements in terahertz (THz) applications, particularly in biomedical conditions. An innovative fork microstrip antenna design has been introduced, operating at THz frequencies, providing multi-band capability, soft characteristics, and high-gain results. The recommended antenna utilizes a series-fed configuration with dual patch elements constructed on a polyethylene substrate, with a thickness of 0.0224 mm, a loss tangent of 0.001, and a permittivity of 2.25. The proposed antenna, with dimensions of 1 × 0.6 × 0.0224 mm³ in its maximum configuration and operating at 0.530 THz and 0.590 THz, exhibits a 10 dB return loss bandwidth of 13 GHz and 15 GHz, respectively. Notably, the realized antenna gain is simulated at 9.01 dBi and 9.53 dBi for their respective frequencies. To assess the antenna's flexibility, simulations are conducted with the antenna configured in bent positions, considering radii of 7 mm, 6 mm, and 5 mm. Furthermore, the study includes an examination of the specific absorption rate (SAR) to validate the suitability of this pliable antenna. The outcomes underscore the potential of the recommended antenna for flexible biomedical THz applications such as the detection of skin tumours and medical imaging.

UWB TAPERED-SLOT PATCH ANTENNA WITH RECONFIGURABLE DUAL BAND-NOTCHES CHARACTERISTICS

An ultra-wideband patch antenna (UWB) that makes use of tapered slot technology is designed and analyzed in this article. Coplanar waveguide feeds the projected antenna. The presented antenna displayed superior UWB performances with -10 dB return-loss bandwidth, ranging from 1.9 to 12 GHz. The projected slot antenna has another benefit of minimizing the interference effect of the narrow band communications conducted by two notch bands operating at 3.3–3.8 GHz (WiMAX) and 5.1-6 GHz (WLAN and HIPERLAN/2), respectively. The Dual-Bands rejection is generated by etching out a complementary split ring resonator (CSRR) from the patch and placing a trapezoidal split ring resonator (TSRR). Adaptable single or dual-band rejection characteristics have been added to the behavior of the UWB antenna, by mounting electronic switching across SRR and CSRR. Furthermore, the presented UWB slot antenna is printed on an FR4-epoxy substrate (εr = 4.4) and it has an overall size of . 55x48x1.5 mm3

Enhancing long-range radar (LRR) automotive applications: Utilizing metasurface structures to improve the performance of K-band Longitudinal Slot Array Antennas

In this paper, we introduce a groundbreaking modification to a K-band substrate integrated waveguide (SIW) Longitudinal Slot Array Antenna for Vehicle-to-Everything (V2X) applications, particularly long-range radar (LRR) in the automotive industry. Our approach harnesses an elliptic metasurface capable of distinguishing between TE and TM modes in relation to radiation direction. By utilizing metasurfaces, we effectively address the issue of mutual coupling between antenna elements, which often results in subpar antenna performance. This modification focuses on improving various antenna characteristics, including frequency bandwidth (expanded by approximately four times), sidelobe level (reduced by 4 dB), aperture efficiency (increased to about 44%), and cross-polarization (reduced by an average of 10 dB). In essence, the results demonstrate that the increased number of longitudinal elements can be effectively enhanced by utilizing the metasurface structure, while maintaining an acceptable level of efficiency. As an illustrative case, we design a 1 × 32-element Longitudinal Slot Array Antenna using the Elliott method operating at 24.3 GHz, with the antenna size measuring 12.5 × 154 mm2. Experimental measurements validate our design, showcasing a 10 dB return loss bandwidth of 24.05–24.45 GHz, a maximum gain of 14.45 dBi, a sidelobe level of 24.5 dB, cross-polarization exceeding 30 dB, and an impressive aperture efficiency of 65%.

A Compact Bandpass Filter with Widely Tunable Frequency and Simple Bias Control

This research paper introduces an innovative design for a compact bandpass filter, notable for achieving a substantial tuning range of operational frequencies using just a single bias voltage. The design is based on a planar microstrip approach, distinguished by its straightforward and efficient structure. Additionally, this filter is characterized by its excellent performance in suppressing out-of-band frequencies. To validate the practicality and effectiveness of this novel design, a compact filter was designed, manufactured, and measured. The testing results were impressive, showing that the filter’s measured center frequency could be tuned across a wide spectrum, from 1.1 to 3.1 GHz, achieving a relative bandwidth of up to 95%. Herein, the relative bandwidth is derived from the calculation of 2(fhigh − flow)/(fhigh + flow). Remarkably, the filter consistently maintains a return loss exceeding 19 dB throughout its tuning range. Additionally, it sustains a 15 dB return loss bandwidth greater than 90 MHz, with the insertion loss varying between a minimum of 0.9 dB and a maximum of 2.1 dB. The compactness of the filter is one of its standout features, with circuit dimensions measuring a mere 0.06λg × 0.09λg (physical dimensions is 13.8 mm × 21.3 mm), where λg represents the wavelength at the filter’s lowest center frequency.

Design of a compact wideband bi-directional pattern antenna for 5G applications

In this research, a wideband bi-directional pattern antenna implemented by a circular monopole encircled with an enforced-radiation circular ring incorporated with inversed L-shaped stub is designed to operate over the mid-band of 5G applications ranging from 2 to 6 GHz. It is contrived of a copper overlaid on FR4 substrate with relative permittivity of 4.3 and height of 1.6 mm. This proposed antenna is fed by a 50-ohm coplanar waveguide, which is printed on the same side of the radiated circular monopole. To further enrich the impedance matching, a pair of etched slots is added-on the ground plane near the fed line to reduce the return loss. In the study, the initial parameters are theoretically worked out, and then simulation is then performed by using an electromagnetic solutions tool to numerically discover the set of solution parameters. From the simulation results, this proposed antenna offers the |S11|<–10 dB covered the operating frequency running from 1.79 to over 8 GHz with fractional bandwidth 126.90 % and 1.74 to 7.07 GHz with fractional bandwidth 101.04 % for the simulation excluded and included SMA, respectively. It provides a linear polarization with total efficiency better than 81.5 %. After that, an antenna prototype with compact dimensions of 45×45×0.6 mm3 was fabricated and testified to validate the simulation results. The measurement results provide a stability bi-directional pattern with peak gain of 5.54 dBi covering a 10 dB return loss bandwidth of 118.5 % (1.93–7.54 GHz). Simulated |S11|, 2D radiation pattern and gain are reasonably in good agreement with experimental results. Furthermore, this proposed antenna is compared with the current compact, wideband and 5G antenna to indicate its prospective for the interested bands

A Bandpass Filter Realized by Using Pixel Structure and Genetic Algorithm Optimization.

This paper presents a flexible method for designing a bandpass filter (BPF) using pixel structure and genetic algorithm (GA) optimization. The pixel structure is made up of a grid of metallic microstrip stubs, and the GA is utilized to determine the connections between these stubs. The pixel structure enables the construction of step impedance and shunt branches, which are used to design a traditional BPF. To enhance the design freedom, one side of the discrete grids is connected to the ground via metallic holes. For verification, a BPF was designed, simulated, and measured. The experimental results showed that the 10 dB return loss bandwidth ranges from 1.1 to 1.9 GHz and the insertion loss is approximately 2.5 dB. There is good agreement between the calculation, EM simulation, and measurement results. The proposed GA-based design method offers significant advantages in terms of one-time EM simulation, feasibility, and labor time savings, making it more convenient than the traditional design method.

Design of a Microstrip Filtering Antenna for 4G and 5G Wireless Networks

The filtering antenna provides both radiation and filtering features and is an important component for the RF front-end of wireless devices. The main function of a filtering antenna is to reject out-of-band signals, thus reducing the interference from adjacent channels. The aim of the present work is to design a 2.6 GHz microstrip filtering antenna for 4G and 5G global mobile services. The filtering antenna is designed using a hairpin bandpass filter integrated with an elliptical microstrip aerial. Good impedance matching is obtained by using appropriate dimensions of the hairpin bandpass filter. The 10 dB return loss bandwidth of the filtering antenna is approx. 5.7%, with the maximum gain for the elliptical filtering antenna of approx. 2.2 dB. Good agreements between the measured and simulated results are obtained for the proposed filtering antenna and the bandwidth covers almost the entire 2.6 GHz band.

Circular Polarized Antenna with Rotationally Positioned Microstrip Structures For UHF RFID Applications

With the use of wireless communication and the industry 4.0 revolution, RFID technology integration in production has increased. The large-scale preference of RFID systems is both cost-effective and significantly increasing production. It is an innovation that provides convenience for large production facilities such as product control, in-plant tracking, storage, inventory operations. In this paper, a compact circularly polarized (CP) reader antenna is presented for ultra-high frequency (UHF) radio frequency identification (RFID) applications. The proposed antenna consists of a circularly slotted ground plane and folded plus-shaped structures with vertical and horizontal positions. Microstrip line feeding technique is used in the vertically folded plus-shaped structure positioned on the front surface. The antenna has a 10 dB return loss bandwidth of 80 MHz (840-920) and a 3 dB axial ratio bandwidth of 20 MHz (855-875). Theproposed antenna has dimensions of 75 × 75 × 1.6 mm3 . The size advantage of the single-layer and singlefed structure enables its applicability in portable systems.

Leaky-Vivaldi antenna covered with metasurface with leaky wave radiation and aperture radiation.

A leaky-Vivaldi antenna covered with metasurface (LVAM) is proposed in this paper. The traditional Vivaldi antenna covered with metasurface realizes backward frequency beam-scanning from -41∘ to 0∘ in the high-frequency operating band (HFOB) and retains aperture radiation in the low-frequency operating band (LFOB). In the LFOB, the metasurface can be regarded as a transmission line to realize a slow-wave transmission. In the HFOB, the metasurface can be considered a 2D periodic leaky-wave structure to realize a fast-wave transmission. The simulated results show that LVAM has the -10 dB return loss bandwidths of 46.5% and 40.0%, and the realized gain of 8.8-9.6 dBi and 11.8-15.2 dBi cover the 5 G Sub-6 GHz band (3.3-5.3 GHz) and the X band (8.0-12.0 GHz), respectively. The test results are in good agreement with the simulated results. As a dual-band antenna covering the 5 G Sub-6 GHz communication band and military radar band, the proposed antenna can guide the future integrated design of communication and radar antenna systems.

Design of new wideband waveguide Magic‐T for X‐band applications

AbstractThe design and fabrication of low loss and wideband Magic‐T with 10 dB return loss (RL) bandwidth over 40% is proposed for X‐band application, which can be used in monopulse comparator network. The proposed Magic‐T is composed of WR90 waveguides include an exponentially conducting cone, metallic multistep l‐shaped septum, and some other conducting posts. By implementation of these optimized conducting cone, septum, and posts, the 20 dB RL bandwidth over 36% is achieved with very low insertion loss (IL) (<0.15 dB) at each port. Moreover, high isolation (>40 dB) across all port over X‐band is another feature of the proposed Magic‐T. The equal power division (in amplitude and phase) at H‐arm and phase cancellation of input power at E‐arm introduce the proposed Magic‐T as a good candidate for sum/difference comparator network for monopulse application. Validation of the simulation results by experimental ones proves the wideband RL, low IL, and high isolation coefficient of the proposed high‐power Magic‐T as well.

Substrate integrated waveguide pedestal filtering-antenna and -arrays for 5G radio frequency front-ends

AbstractThis paper presents the design, manufacturing, and measurement of a novel substrate integrated waveguide (SIW) pedestal filtering antenna solution for use in 5G New Radio sub-6 GHz communications. Miniaturization is achieved through the use of SIW pedestal resonators and integration of the radiating element into the filter design, resulting in higher order suppression. The design generates a third order filtering response utilizing SIW pedestal resonators and a patch antenna element. The manufactured SIW pedestal filtenna achieves a 10 dB return loss bandwidth of 4.29% about a center frequency of 3.63 GHz, and a boresight gain of 3.66 dBi. Using the SIW pedestal filtenna elements, two array configurations are measured, a 1 × 1 linear array and 2 × 2 planar array. Beam-steering capability for the linear array is demonstrated in simulation, while the 2 × 2 array is shown to be suited to both dual- and single-mode operation.

Coplanar integration of antipodal vivaldi antenna with metasurface antennas for ground penetrating radar and 5–GHz WIFI applications

In this paper, we design a novel antenna with dual-band and multi-radiation modes by integrating the two metasurface binary array antennas (MBAAs) into the antipodal Vivaldi antenna (AVA). Metasurface binary array antenna 1 (MBAA-1) and metasurface binary array antenna 2 (MBAA-2) are symmetrically embedded on two radiation patches of AVA. When AVA is excited, vertical down radiation can be achieved. When MBAA-1 or MBAA-2 is excited, horizontal forward or backward radiation can be achieved. The simulated results show that AVA and MBAAs have the −10 dB return loss bandwidths of 163.6% and 9.3% and the realized gain of 5.5–8.1 dBi and 8.0–10.0 dBi cover the Ground Penetrating Radar (GPR) band (0.6–6.0 GHz) and the 5–GHz WIFI band (4.9–5.9 GHz), respectively. The test results are in good agreement with the simulated results. The proposed antenna realizes the integrated design of 5–GHz WIFI and GPR antennas, which can be applied to the antenna system design of intelligent robots and UAVs, and contribute to the integration development of wireless communication and radar in the future.

Analysis and Design of an Ultrawideband Dual-Polarized Antenna for IBFD Applications

This communication investigates design requirements for a class of dual-polarized in-band full-duplex (IBFD) antennas utilizing a symmetry of structures and a differential-feeding scheme. The analysis reveals that, to achieve zero coupling between two ports, the out-of-phase power divider (PD) does not need to have perfect isolation and perfect matching at the two output ports. A more relaxed set of requirements for the PD is derived for the first time. Based on this, an ultra-wideband cross-shaped Vivaldi antenna is designed for IBFD applications with very high isolation. The measured 10 dB return loss bandwidth is 1.26–8.0 GHz (145.5%), while the measured port-to-port isolation is >42 dB at 1.26–4.7 GHz (115.4%) and >34 dB within the whole operational bandwidth.

Design of microstrip Yagi‐Uda antenna array for 4.5 GHz band fixed wireless access in 5G

AbstractFixed wireless is a part of wireless local area network (WLAN) infrastructure which connects two fixed locations, like, tower to building or building to building by radio link or by other wireless link. In fifth generation (5G) for fixed wireless access (FWA) one of the attractive bands is 4.5 GHz band. The designs of a microstrip Yagi‐Uda antenna and a 4‐element Yagi‐Uda array for the application to 5G FWA at 4.5 GHz band are reported here. The experimentally investigated impedance and radiation properties of Yagi‐Uda antenna and a 4‐element array of it are reported. The antenna has 10 dB return loss bandwidth of 580 MHz which is 12.8% of the centre frequency and the array has bandwidth of 520 MHz which is 11.7% at the centre frequency. The Yagi‐Uda antenna array beam is tilted by 46° from the broadside direction. The measured maximum gains of the Yagi‐Uda antenna and the 4‐element array are 7.2 and 16.5 dBi, respectively. The cross‐polarization levels lower by about 20 dB than the main lobes are observed. The Yagi‐Uda array has high front‐to‐back ratio of better than 25 dB. The measured results are compared with the simulated results.

Increasing the Gain of Beam-Tilted Circularly Polarized Radial Line Slot Array Antennas

This article presents a new type of beam-tilted circularly polarized (CP) radial line slot array (RLSA) antennas. When the conventional beam tilting method is applied to CP-RLSA antennas, the aperture efficiency of the antenna degrades significantly due to very sparse slots in some parts of the antenna. A new method is presented to prevent this, and hence a much higher gain and aperture efficiency are achieved from the same antenna area. The key to the new method is an aggressively biased truncation of the slot layout that leaves out sparse slots. Consequently, the feed point moves closer to an edge of the TEM waveguide. A reflecting wall is introduced to prevent leakage from this edge. It is shown that the gain of RLSAs with beams tilted to 25° and 45° (measured from normal direction) can be increased by 5.5 dB (from 20.5 to 26 dBic) using the new method as opposed to the conventional method. The new concept and predicted results are validated using a prototype antenna with the beam-tilted to an angle of 25°. The aperture diameter and overall thickness of the prototype are <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$12\lambda _{0}$ </tex-math></inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.4\lambda _{0}$ </tex-math></inline-formula> , respectively, where <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 the operating frequency of 18 GHz. The measured results confirmed a higher gain of 26.2 dBic, an aperture efficiency of 30%, the overall efficiency of 93.2%, and sidelobe levels (SLLs) less than −25 dB at 18 GHz. The measured 10 dB return loss bandwidth of the antenna is greater than 63.7%, 3 dB axial-ratio bandwidth is 13.3%, and 3 dB gain bandwidth is 6.7%.

28 GHz and 38 GHz Dual-Band Vertically Stacked Dipole Antennas on Flexible Liquid Crystal Polymer Substrates for Millimeter-Wave 5G Cellular Handsets

Minimizing the size of mobile antennas is necessary for integrating the components inside a mobile device. Wideband and multiband antennas are also required to cover various 5G mobile communication frequency spectra. This article presents a vertically stacked dipole antenna array operating in the 28/38 GHz dual-band. The proposed antenna is small and satisfies the need for wide bandwidth in the form of a dual band. The antenna structure has symmetric 38 GHz band radiators positioned above and below a multilayer substrate, and a 28 GHz band radiator positioned on the middle plane, providing a dual-band antenna structure with small lateral width. Herein, two types of antenna structures are proposed, each with a single-ended and differential feed structure for compatibility with various RF front ends. The single antenna yields &#x2212;10 dB bandwidth for return loss of 23.9&#x0025; and 14.4&#x0025;, and gain of 4.8 and 4.6 dBi at 28 and 38.5 GHz, respectively. The 4-element antenna array yields a gain of 9.0 dBi at 28 GHz and 10.3 dBi at 38.5 GHz. It was fabricated on a flexible substrate and can be bent and inserted into the lateral edge of the terminal. The proposed antenna elements and arrays satisfy the performance factors requisite for millimeter wave 5G communication including compact size, wideband, dual-band, and adequate gain.

A Wideband Fabry-Pérot Antenna With Enhanced Gain in the High-Frequency Operating Band by Adopting a Truncated Field Correcting Structure

A novel method to enhance the high-frequency gain of a wideband Fabry–Pérot (FP) antenna by using a truncated field correcting structure (TFCS) is proposed. The TFCS is formed by laminated dual-layer dielectric substrates and acts as the high-frequency operating band phase and amplitude correcting structure of the FP antenna for the radiated field. This method not only has a small effect on the operating bandwidth of the antenna, but also has a positive effect on improving the gain over the low-frequency operating band. The simulation and experimental results verify that the TFCS can effectively enhance the gain within the high-frequency operating band, and expand the 3 dB gain bandwidth of the FP antenna. The measured results show that the proposed antenna has a 10 dB return loss bandwidth of 8.49–12.34 GHz (37.0%), a 3 dB gain bandwidth of 8.48–11.82 GHz (32.9%), and a maximum gain of 17.73 dBi. The 3 dB gain bandwidth of the FP antenna is extended from 28.8% to 32.9% after loading with the TFCS, and the maximum gain enhancement within the high-frequency operating band is increased by 3.48 dB at 11.58 GHz.

Miniaturized Dual-Band Broadside/Endfire Antenna-in-Package for 5G Smartphone

This paper proposes a miniaturized antenna in package (AiP) for 5G millimeter-wave smartphone that incorporates broadside and end-fire arrays and supports a dual band covering 28 and 39 GHz. This paper demonstrates that the proposed AiP is 5.8 mm × 19 mm × 1.122 mm. It is believed that this is the smallest 5G AiP that can support a 10 dBi antenna gain, a 10 dB return-loss bandwidth of 3 GHz, and more than 10 dB isolation for both broadside and end-fire arrays. AiP consists of a 1 × 4 patch antenna array for broadside radiation and a 1 × 4 dipole antenna array for end-fire radiation. To miniaturize the patch antenna elements, a multi-layer Reactive Impedance Surface (RIS) is embedded between the patch layer and the ground plane. This multi-layer RIS idea greatly fits in 5G PCB-stack up antennas where each stack-up layer essentially requires certain portion of copper area. For the end-fire array antenna miniaturization with bandwidth improvement is achieved by modifying the Vertically Bent Folded Dipole Antenna (VBFDA) and adding a tightly-coupled T-shape side via wall. The AiP achieves a 10 dB return-loss bandwidth of 26.22 to 29.57 GHz and 35.18 to 41.00 GHz for Multi-Layer RIS Patch Antenna(MLRPA), and 26.40 to 29.74 GHz and 36.65 to 40.72 GHz for VBFDA. The antenna gain is 11.6 dBi for MLRPA and 10.0 dBi for VBFDA.

Center-Slotted Wideband Hybrid 10 dB Coupler

In this paper, a wideband microstrip hybrid coupler designed, simulated, built and tested. These couplers have advantage of easy fabrication, lightweight and incorporation with other microwave devices and validated using 3D planar electromagnetic softwares like Sonnet Suites. The final design is composition of two parallel lines with symmetric slits and a center slot. Directional coupler is designed and simulated to operate in the frequency range from 1 GHz to 5 GHz with 2.4 Ghz coupling -10 dB return loss bandwidth between 1.6 - 4 GHz. The fabricated coupler shows good agreement between measured and simulated results with very low isolation characteristics. Four symmetric orthogonal U-Shaped structures at the center of the coupling region distinguishes the proposed design with other works. It makes significant improvement in calculation duration thereby achieving lower response latency and lowers the possible manufacturing errors compared with previously published similar works.