Ultra wideband patch antenna with a novel folded-patch technique

The authors present the results of a polygonal patch antenna for ultra-wideband applications covering a frequency band from 4.14 to 13.50 GHz. The fabricated antenna achieved a 210 dB impedance bandwidth in excess of 125% with an antenna size of 0.373λo/sub / x 0.373 xλo/sub /0.149λ/spl o/ at its centre frequency. The antenna?s impedance bandwidth is 64% higher than what is currently obtainable with state-of-the-art folded-patch techniques. The proposed patch antenna has a polygonal-shape with a rectangular slot and shorting pins. The analysis of this antenna shows that bandwidth broadening is achieved by using a rectangular slot on the patch that is fed from a folded-patch feed, whereas the reduction in antenna size is achieved through the use of two shorting pins strategically located on the radiating patch.     

Dual layer stacked rectangular microstrip patch antenna for ultra wideband applications

An antenna consisting of a U-slotted rectangular microstrip patch stacked with another patch of a different size on a separate layer is presented and its performance results are investigated. An equivalent circuit model of this stacked patch design structure is also presented based on an extended cavity model to predict the input impedance. The theoretical input impedance is evaluated from this circuit model and the experimental results support the validity of the model. In this case, stacking with a simple patch adds another resonance to the antenna thus providing a wider bandwidth. The dimension of the top patch is optimised to achieve ultra wide bandwidth. A maximum impedance bandwidth of 56.8% is achieved using this structure, and the return loss |S₁₁|of the antenna is less than -10 dB between 3.06 and 5.49 GHz and the radiation patterns are found to be relatively constant throughout the band. A coaxial feed with Gaussian modulated pulse is used for this antenna.     

新型宽频带微带贴片天线的设计

提出了一种新颖的展宽三角形微带贴片天线工作频带的设计方法．通过在三角形微带贴片侧边附近加载与之平行的缝隙来实现双频工作,并添加一对平行于底边的缝隙使两个频点靠近,利用仿真软件进行优化,有效地展宽了贴片天线的频带．制作了实际的贴片天线,结果表明所设计天线的工作带宽(VSWR<2)是普通三角形微带天线的4.46倍,且天线尺寸与同频率的常规贴片天线相比缩小了9.3%．测量结果与仿真结果吻合,证明了所提方法的有效性．     

Internal triple-band folded planar antenna design for third generation mobile handsets

A novel internal triple-band folded planar antenna for mobile handsets is introduced, formed by modifying the geometry of a rectangular patch antenna to include a shorting pin, folded sides, a shorted microstrip stub and a notch. The size of the antenna is successfully reduced to a volume of 34 times 34 times 7 times mm³. The antenna is mounted on a finite ground plane of 50times100 times mm². The impedance bandwidth achieved was 29.7% (equivalent to return loss%%10%dB); this covers the DCS1800, PCS1900 and UMTS 2000 bands. The characteristics of the proposed antenna, including impedance bandwidth and far field radiation patterns are discussed theoretically and experimentally; the simulated and measured results show good agreement. The tuning effects of the geometry parameters on impedance matching of the proposed antenna are also investigated.     

A Novel Compact Highly Isolated UWB MIMO Antenna with WLAN Notch

This paper presents a compact Multiple Input Multiple Output (MIMO) antenna with WLAN band notch for Ultra-Wideband (UWB) applications. The antenna is designed on 0.8 mm thick low-cost FR-4 substrate having a compact size of 22 mm × 30 mm. The proposed antenna comprises of two monopole patches on the top layer of substrate while having a shared ground on its bottom layer. The mutual coupling between adjacent patches has been reduced by using a novel stub with shared ground structure. The stub consists of complementary rectangular slots that disturb the surface current direction and thus result in reducing mutual coupling between two ports. A slot is etched in the radiating patch for WLAN band notch. The slot is used to suppress frequencies ranging from 5.1 to 5.9 GHz. The results show that the proposed antenna has a very good impedance bandwidth of |S11| < −10 dB within the frequency band from 3.1–14 GHz. A low mutual coupling of less than −23 dB is achieved within the entire UWB band. Furthermore, the antenna has a peak gain of 5.8 dB, low ECC < 0.002 and high Diversity Gain (DG > 9.98).     

Wideband microstrip antennas with sandwich substrate

A broadband microstrip antenna with low?high?low (sandwich) dielectric constant substrate combination using a microstrip line-via feed is presented for ultra-wideband applications. The proposed antenna consists of three dielectric substrates; low dielectric constant substrates that contain the microstrip feed line as well as parasitic patches and a high dielectric constant substrate that contains the driven patch. To achieve a large impedance bandwidth, parasitic patches and microstrip line-via combination feed to the driven patch in the multilayered microstrip antenna are used. The proposed antenna designed, fabricated and measured on the sandwich substrate. The antenna has measured 10 dB return loss bandwidth of 46.9% and directive gain .5.2 dBi at boresight across the impedance bandwidth. The total height of antenna is 5.77 mm or 0.077λ ^{at 4 GHz.}     

Broadband designs of coplanar capacitivelyfed shorted patch antennas

The author presents a coplanar capacitively fed shorted patch antenna for easy fabrication and providing a very wide impedance bandwidth. In this design, a feeding strip is located on the same plane as that of the radiating patch and used to excite the antenna by electromagnetic coupling. Experimental results reveal that the impedance bandwidth of the proposed antenna depends not only on the length and location of the feeding strip but also on the width of the radiating patch. For the optimal result obtained in the design, the 10 dB return-loss impedance bandwidth is as large as 78%. The radiation characteristics of the operating frequencies within the obtained wide bandwidth are also studied and presented.     

Metamaterial-Based Compact Antenna with Defected Ground Structure for 5G and Beyond

In this paper, a unit cell of a single-negative metamaterial structure loaded with a meander line and defected ground structure (DGS) is investigated as the principle radiating element of an antenna. The unit cell antenna causes even or odd mode resonances similar to the unit cell structure depending on the orientation of the microstrip feed used to excite the unit cell. However, the orientation which gives low-frequency resonance is considered here. The unit cell antenna is then loaded with a meander line which is parallel to the split bearing side and connects the other two sides orthogonal to the split bearing side. This modified structure excites another mode of resonance at high frequency when a meander line defect is loaded on the metallic ground plane. Specific parameters of the meander line structure, the DGS shape, and the unit cell are optimized to place these two resonances at different frequencies with proper frequency intervals to enhance the bandwidth. Finally, the feed is placed in an offset position for better impedance matching without affecting the bandwidth The compact dimension of the antenna is 0.25 λL × 0.23 λL × 0.02 λL, where λL is the free space wavelength with respect to the center frequency of the impedance bandwidth. The proposed antenna is fabricated and measured. Experimental results reveal that the modified design gives monopole like radiation patterns which achieves a fractional operating bandwidth of 26.6%, from 3.26 to 4.26 GHz for |S11|<−10 dB and a pick gain of 1.26 dBi is realized. In addition, the simulated and measured cross-polarization levels are both less than −15 dB in the horizontal plane.     

A novel design of a cpw‐fed single square‐loop antenna for circular polarization

Abstract

The experimental and simulated results for the proposed antenna are investigated in this article. Moreover, a novel broadband design of a circularly polarized (CP) single square slot antenna fed by a single coplanar waveguide is presented. By appropriately choosing the circumference of the square‐loop, the length of the protruded strip, and the gap, this proposed antenna thus owns good CP radiation and good impedance match simultaneously at the frequency of 2.45 GHz. This proposed antenna has the fundamental resonant frequency of 2.5 GHz with the minimum return loss of ‐39.9 dB. Furthermore, its impedance bandwidth is 460 MHz or 18.4% and 3‐dB axial‐ratio (AR) bandwidth is 360 MHz or 14.4% at 2.5 GHz.     

Broadband flexible comb-shaped monopole antenna

A broadband comb-shaped monopole antenna is proposed. The antenna has dimensions of 19 mm x 12 mm. The measured results show good agreement with the numerical prediction, and broadband operation with 10 dB impedance bandwidth of 44.75% (1.7-2.68 GHz). The antenna is built on one side of a flexible-printed circuit board (PCB) dielectric substrate. Folded and rolled antenna structures, which are transformed by the proposed planar antenna structure, are presented. Each antenna has a broadband impedance bandwidth that covers the PCS, UMTS, WiBro, WLAN and SDMB bands. Also, omni-directional radiation patterns over the operating bands have been obtained. The proposed antennas are suitable for mobile communication applications requiring a small antenna.     

Ultra-wideband CPW-fed antenna with round corner rectangular slot and partial circular patch

Abstract: A novel coplanar waveguide (CPW)-fed ultra-wideband wide slot antenna is proposed. Because of the round corner of the rectangular slot and partial circular patch, the bandwidth of the antenna is enhanced largely. Good agreement between the measurement and simulation has been achieved. The results show that the impedance bandwidth of the antenna reaches up to 4.5-15.5 GHz for S₁₁ < -15 dB and 2.5-18 GHz for S₁₁ < -10 dB. Meanwhile, a good omni-directional radiation performance has also been achieved.     

基于LTCC宽频带双频差分天线的研究与设计

提出了一种新型宽频带双频差分天线.该天线基于低温共烧陶瓷(Low Temperature Co-Fired Ceramies,简称LTCC)技术,采用矩形环状贴片,并使用两条叉形微带馈线进行差分馈电,是一种具有平衡结构的宽缝隙天线,该结构使得天线拥有很宽的频带宽度.天线两频段的中心频率为2.63 GHz和5.13 GH...     

Multipatches multilayered UWB microstrip antennas

The authors present multipatches multilayered ultra-wideband (UWB) microstrip antennas. The antenna comprises a driven patch radiator with five parasitic patch radiators. Two antennas with different dielectric substrate combinations are studied. The antenna with low-high-low dielectric constant substrate combination (Antenna no. 1) has an improved performance in terms of impedance bandwidth, gain, overall antenna size and beam-squinting over the antenna with low-low-low dielectric constant substrate combination (Antenna no. 2). The low-high-low dielectric constant combination consisting of three dielectric substrates, namely low dielectric constant (ϵr = 3.38) for both bottom and upper substrate but, high dielectric constant (ϵr = 6.15) for middle substrate. Five parasitic patches and multi-dielectric layers are used for wide impedance bandwidth and less boresight gain variation with frequency. A measured 10 dB return loss bandwidth of 48% with boresight gain .5.0 dBi is achieved. Antenna no. 1 can have 8% wider impedance bandwidth, 40% overall area reduction and less beam-squinting compared with Antenna no. 2.     

Analysis and design of broadband U-slot cut rectangular microstrip antennas

Broadband microstrip antenna using variations of U-slot has been widely reported. However, in most of the reported work, an in-depth explanation about the mode introduced by U-slot and procedure to design U-slot cut antennas at any given frequency is not explained. In this paper, first an extensive analysis to study the broadband response in symmetrical and a new configuration of asymmetrical U-slot cut rectangular microstrip antennas is presented. The U-slot tunes higher-order orthogonal mode resonance frequency of the patch with respect to fundamental mode to realise wider bandwidth. Further formulation in resonant length at modified patch modes in symmetrical U-slot cut antenna is proposed. Frequencies calculated using these formulations show closer agreement with simulated and measured results. Using proposed formulations, a procedure to design U-slot cut antenna at different frequencies over 800–4000 MHz range which shows broadband response is explained. Thus, the proposed work gives an insight into the functioning of widely used U-slot cut antennas and the formulations will be helpful for designing at any given frequency.     

A Compact Flexible Circularly Polarized Implantable Antenna forBiotelemetry Applications

With the help of in-body antennas, the wireless communication among the implantable medical devices (IMDs) and exterior monitoring equipment, the telemetry system has brought us many benefits. Thus, a very thin-profile circularly polarized (CP) in-body antenna, functioning in ISM band at 2.45 GHz, is proposed. A tapered coplanar waveguide (CPW) method is used to excite the antenna. The radiator contains a pentagonal shape with five horizontal slits inside to obtain a circular polarization behavior. A bendable Roger Duroid RT5880 material (ε_r = 2.2, tanδ = 0.0009) with a typical 0.25 mm-thickness is used as a substrate. The proposed antenna has a total volume of 21 × 13 × 0.25 mm³. The antenna covers up a bandwidth of 2.38 to 2.53 GHz (150 MHz) in vacuum, while in skin tissue it covers 1.56 to 2.72 GHz (1.16 GHz) and in the muscle tissue covers 2.16 to 3.17 GHz (1.01 GHz). GHz). The flexion analysis in the x and y axes was also performed in simulation as the proposed antenna works with a wider bandwidth in the skin and muscle tissue. The simulation and the curved antenna measurements turned out to be in good agreement. The impedance bandwidth of −10 dB and the axis ratio bandwidth of 3 dB (AR) are measured on the skin and imitative gel of the pig at 27.78% and 35.5%, 13.5% and 4.9%, respectively, at a frequency of 2.45 GHz. The simulations revealed that the specific absorption rate (SAR) in the skin is 0.634 and 0.914 W/kg in muscle on 1g-tissue. The recommended SAR values are below the limits set by the federal communications commission (FCC). Finally, the proposed low-profile implantable antenna has achieved very compact size, flexibility, lower SAR values, high gain, higher impedance and axis ratio bandwidths in the skin and muscle tissues of the human body. This antenna is smaller in size and a good applicant for application in medical implants.     

Compact active integrated microstrip antennas with circular polarisation diversity

A compact active integrated microstrip antenna with circular polarisation (CP) diversity for a global positioning system (GPS) receiver is presented. As a radiator, a diamond-shaped micro- strip ring patch with four embedded slots has been newly proposed to realise wide impedance bandwidth, compact size and dual CP. The active circuitry, consisting of both switching circuits and a small signal amplifier, is placed at the square opening inside the radiator. Thus, all electrical parts are mounted on the top layer of the circuit board. CP diversity is achieved by the switching circuit, and its output signal is amplified. The proposed antenna has been simulated and fabricated on the FR-4 PCB board. The size of the fabricated active antenna, including the radiator and active circuitry, is only about 57% of a conventional square-microstrip antenna with a side of half wavelength. From the measured radiation patterns and CP bandwidth for either polarisation selection, it is proven that this antenna has successfully performed the polarisation diversity. In addition, the measured minimum antenna gain of 12 dBi is estimated to be good enough to improve the GPS receiver performance.     

Design of a Mechanical Tuning for Superconducting Microwave Power Filters

We have been studying microwave superconducting power filters with dynamic tunable mechanism. This paper reports estimation of superconducting microstrip patch resonators using piezoelectric actuators as parts of the electrically tunable mechanism. We carried out electromagnetic (EM) simulations on the proposed tunable patch resonators. The main conditions of the EM simulations were that the superconducting material was YBCO, the patch pattern with TM₁₁ or TM₀₁-resonant mode was disk shape, and so on. From the EM simulation results, it was estimated that the resonant mode differences of the unloaded-Q, the power handling capability, and the resonant frequency tunability related with the PZT bimorph element as the actuator candidate.     

Wideband multilayered microstrip antennas fed by coplanar waveguide-loop with and without via combinations

Coplanar waveguide (CPW)-loop fed wideband multilayered microstrip antennas with and without via combinations are presented. The antenna consists of two dielectric substrates, CPW-loop on the ground plane layer, main patch on the middle layer and four asymmetric parasitic patches on the upper layer. The feed consists of a CPW, a loop on a ground plane and a via between main patch and feeding strip on the ground plane layer. Using via, the gain flatness over the impedance bandwidth and return loss are improved. The proposed antenna with four feeding structures is also studied. The 10 dB return loss bandwidths of the antenna with and without via are 34% (3.12? 4.41 GHz) and 33.7% (3.18 ?4.47 GHz), respectively. The measured gain is >5.0 dBi over the impedance bandwidth.     

Super Compact UWB Monopole Antenna for Small IoT Devices

This article introduces a novel, ultrawideband (UWB) planar monopole antenna printed on Roger RT/5880 substrate in a compact size for small Internet of Things (IoT) applications. The total electrical dimensions of the proposed compact UWB antenna are 0.19 λ_o × 0.215 λ_o × 0.0196 λ_o with the overall physical sizes of 15 mm × 17 mm × 1.548 mm at the lower resonance frequency of 3.8 GHz. The planar monopole antenna is fed through the linearly tapered microstrip line on a partially structured ground plane to achieve optimum impedance matching for UWB operation. The proposed compact UWB antenna has an operation bandwidth of 9.53 GHz from 3.026 GHz up to 12.556 GHz at −10 dB return loss with a fractional bandwidth (FBW) of about 122%. The numerically computed and experimentally measured results agree well in between. A detailed time-domain analysis is additionally accomplished to verify the radiation efficiency of the proposed antenna design for the ultra-wideband signal propagation. The fabricated prototype of a compact UWB antenna exhibits an omnidirectional radiation pattern with the low peak measured gain required of 2.55 dBi at 10 GHz and promising radiation efficiency of 90%. The proposed compact planar antenna has technical potential to be utilized in UWB and IoT applications.     

Josephson Bicrystal Junctions on Sapphire Substrates for THz Frequency Application

Thin film metal oxide superconducting bicrystal junctions on sapphire substrates with I _c R _N products up to 2.5 mV at 4.2 K for width 4 μm and normal-state junction resistance 10–60 Ω were fabricated and characterized at dc and THz frequency. Three types of samples—one with broadband log-periodic antenna, another with double-slot antenna for 300 GHz and third one with double-slot antenna for 400 GHz—have been investigated at THz frequency. New design of antenna coupling with Josephson junction was elaborated for minimization of THz frequency losses in superconducting film. For a particular case of f=320 GHz double-slot antenna, a ratio for bandwidth Q = f/Δf ≈ 10 was measured.