Showing papers on "Feed line published in 2019"

A Modified Meander Line Microstrip Patch Antenna With Enhanced Bandwidth for 2.4 GHz ISM-Band Internet of Things (IoT) Applications

Abstract: Internet of Things (IoT) based application requires integration with the wireless communication technology to make the application data readily available. In this paper, a modified meander shape microstrip patch antenna has been proposed for IoT applications at 2.4 GHz ISM (Industrial, Scientific and Medical) band. The dimension of the antenna is 40×10×1.6 mm 3 . The antenna design is comprised of an inverse S-shape meander line connected with a slotted rectangular box. A capacitive load (C-load) and parasitic patch with the shaped ground are applied to the design. Investigations show that the antenna designed with an inverse S-shape patch and connecting rectangular box in the microstrip line has a higher efficiency and gain compare to the conventional meander shape antenna. The C-load is applied to the feed line to match the impedance. Moreover, parametric studies are carried out to investigate the flexibility of the antenna. Results show that, the gain and efficiency can be improved through adjusting the rectangular box with applying parasitic element and the shaped ground. The parasitic element has high impact on the bandwidth of the antenna of 12.5%. The finalized antenna has a peak gain of -0.256 dBi (measured) and 1.347 dBi (Simulated) with 79% radiation efficiency at 2.4 GHz. To prove the efficiency and eligibility in IoT applications, the measurement of the power delivered and received by the antenna at 2.4 GHz is performed and compared with the results of a dipole antenna. The antenna is integrated with 2.4 GHz radio frequency module and IoT sensors to validate the performance. The antenna novelty relies on the size compactness with high fractional bandwidth that is validated through the IoT application environment.

A compact UWB monopole patch antenna with reconfigurable Band-notched characteristics for Wi-MAX and WLAN applications

Abstract: A compact planar monopole elliptical UWB antenna with a microstrip band-stop filter using a Slot-Type Split-Ring Resonator (ST-SRR) is analyzed and presented in this paper. In order to improve the impedance matching and operating bandwidth of the proposed antenna, a partial defected ground plan is utilized. The ST-SRR structure is inserted into the center of the feed line of the UWB antenna to achieve notch band characteristics to reject interference with the wireless local area network (WLAN) IEEE802.11a/h/j/n (5.15–5.35 GHz, 5.25–5.35 GHz, 5.47–5.725 GHz, 5.725–5.825 GHz) and Wi-Max (IEEE802.16 3.30–3.80 GHz). A pin diode is inserted in the ST-SRR structure in order to achieve reconfigurability in the notch band function. The measured result shows that the proposed antenna operates over 2.7 to 14.9 GHz with a fractional bandwidth of 138.63% for S11 ≤ −10 dB. By controlling the PIN diode at OFF and ON states, the notch bands of the proposed UWB can be switched in the range of 3.43–3.75 GHz and 4.87–6.40 GHz, respectively. Good agreement between the simulated and measured results is achieved. The obtained results show that the proposed antenna is a good candidate for reconfigurable UWB communication applications.

A modified microstrip line fed compact UWB antenna for WiMAX/ISM/WLAN and wireless communications

Abstract: A novel design of compact UWB antenna is presented using a spanner shaped microstrip line. The proposed antenna consists of a rectangular patch with step slot at one of the lower edge and the defected ground plane embedded with a mirror imaged ‘P’ shaped slot. By using the novel spanner shaped feed line, the measured bandwidth of 153.22% (2.94–22.2 GHz) for VSWR ≤ 2 is achieved. The realised gain of the antenna is calculated and it is varying from −1.38 to 5.18 dB for the entire band of operation. The radiation patterns of the antenna are measured at 3.1, 6.85, 10.6 and 18 GHz which includes lower, middle and upper cut off frequencies of UWB region. The prototype of the design is fabricated and measurement is carried out in order to validate the proposed results. Also, the time domain analysis is performed to calculate the group delay and fidelity factor which are satisfying the UWB limits.

Electrically compact srr-loaded metamaterial inspired quad band antenna for bluetooth/wifi/wlan/wimax system

Abstract: In this paper, we reveal a concept of low-profile Split Ring Resonator loaded metamaterial inspired antenna for Bluetooth/WiFi/WLAN/WiMAX communication systems. The antenna’s overall dimensions are 30 × 31 mm2 where two metamaterial unit cells are placed parallel to each other and a zig-zag feed line is connected with the SubMiniature version A connector. The defected ground technique was used to improve the antenna’s operational bandwidth. The computer simulation technology Microwave Studio was used to design and perform the numerical investigation, and the antenna was fabricated on FR-4 dielectric material. The Agilent N5227A VNA and anechoic chamber-based Satimo Star Lab were used to measure the antenna’s scattering parameters, voltage standing wave ratio, gain, efficiency and radiation patterns. The proposed metamaterial antenna had 200 MHz (2.40–2.60 GHz) and 390 MHz (3.40–3.79 GHz) overall bandwidth, which are similar to the simulated data. The measured results were applicable for Bluetooth (2.40–2.485 GHz), WiFi (2.4 GHz), WLAN (2.40–2.49 GHz and 3.65–3.69 GHz), and WiMAX (3.40–3.79 GHz) applications. The antenna’s average gain was 1.50 dBi, with the maximum and minimum gains of 2.25 dBi and 0.88 dBi, respectively, in addition to omnidirectional radiation patterns at operating bands.

Miniaturised UWB antenna with dual-band rejection of WLAN/WiMAX using slitted EBG structure

Abstract: This study presents a new slitted electromagnetic bandgap (EBG) structure to filter undesired wireless local area network (WLAN) and worldwide interoperability for microwave access (WiMAX) bands in the ultra-wideband (UWB) spectrum. A simple UWB antenna which consists of a microstrip tapered feed line, a circular patch and a defected ground structure is used as a reference antenna. The antenna is then integrated with a slitted EBG structure near the feed line to notch two interfering bands. The created notched bands by the EBG structure can be independently controlled. Owing to structural symmetry of the proposed antenna, the size can be reduced by approximately half to form a miniaturised antenna. The miniaturised antenna has the same full-size antenna characteristics with little change in the notched bands specifications. Frequency domain measurement results show that the full-size and miniaturised antennas have a flat transfer function, and a group delay variation of about 0.5 ns in the entire UWB band except for the notched bands.

New design of UWB-MIMO antenna with enhanced isolation and dual-band rejection for WiMAX and WLAN systems

Abstract: In this work, a new design of wide-band multiple-input multiple-output (MIMO) antenna with improved isolation and dual-band rejection is proposed for wireless systems operating over the entire ultra-wide-band (UWB), X-band, and Ku-band (3–18 GHz). The proposed four-element UWB-MIMO antenna is fabricated on Rogers RT/Duroid-5880 substrate with dimension of 73 × 73 × 0.79 mm 3 . It achieves high isolation (>20 dB) between antenna elements without using any decoupling structures. In order to prevent interference problems from nearby WiMAX (3.3–3.8 GHz) and WLAN (5.1–5.8 GHz) systems, a C-shaped stub is embedded in the radiating patch and a pair of U-shaped parasitic strips is inserted beside the feed line in the single element design. The effectiveness of the proposed design is demonstrated by investigating measurement and simulation results, and comparing them with other existing designs. The results show that the proposed design has an input reflection coefficient <−10 dB, a mutual coupling <−20 dB, and an omnidirectional radiation pattern across the bandwidth of interest (3–18 GHz) excluding the two rejected bands. Also, the proposed design exhibits high diversity performance in terms of envelope correlation coefficient (ECC <0.0015) and channel capacity loss (CCL < 0.3 bits/s/Hz). This reveals the effectiveness of the proposed design in wide-band wireless applications such as satellite communications and microwave medical imaging.

60 GHz Low-Profile, Wideband Dual-Polarized U-Slot Coupled Patch Antenna With High Isolation

Abstract: This paper presents a low-profile, highly isolated, wideband, U-shaped slot-coupled dual-polarized patch antenna for the 60 GHz frequency band. The proposed antenna exhibits broadband characteristics that entirely cover the 60 GHz industrial, scientific, and medical (ISM) band, by forming additional resonance at the U-shaped coupled slot. The port isolation is improved by up to 38.6 dB via circulating current in the feed line of the isolation port, which is caused by a reverse placement between the current distributions of the circular patch and U-shaped slot. This phenomenon occurs at the resonant frequency point of the circular patch and is caused by inducing currents of the U-shaped slot and the patch orthogonally to the feeding line. The $2.2 \times 2.2\times 0.066\lambda _{0}^{3}$ -sized antenna exhibits a 15% impedance bandwidth, 20.4% 3 dB gain bandwidth, and 8.6 dBi peak gain. The port and polarization isolations of the proposed antenna are higher than 37.2 and 18 dB, respectively. When compared with other reported millimeter-wave dual-polarized antennas, the proposed antenna shows the widest 3 dB gain bandwidth and the highest isolation with the lowest profile.

A CPW-fed compact monopole antenna with defected ground structure and modified parasitic hilbert strip having wideband circular polarization

Abstract: A novel CPW-fed monopole antenna with wideband circular polarization is proposed. The antenna consists of a basic rectangular monopole, fed by a 50 Ω microstrip line, through partial asymmetric impedance steps to attain wideband characteristics. On either side of the feed line, there are sections of partial, asymmetric ground planes. The ground plane on the left is appended with a rectangular stub and a step notch. Wideband circular polarization is achieved by using a strip around the upper end of the monopole and also by a parasitic modified Hilbert strip to the right of the monopole. The monopole, the upper parasitic strip and the modified parasitic Hilbert strip are coupled together by proximity coupling yielding the wide bandwidth. The antenna has been fabricated and the simulated and measured results were compared. The antenna has an impedance bandwidth ranging from 2.04 GHz to 7.95 GHz (118.2%) and an axial ratio bandwidth ranging from 3.6 GHz to 6.84 GHz (62%), thus covering the Wireless Local Area Network (WLAN) 5.2/5.8 GHz, the Worldwide interoperability for Microwave Access (WiMAX) 3.5/5.5 GHz and also partially covering the C-band (4–8 GHz). The antenna shows good radiation characteristics and obtains a reasonable gain over the entire operating frequency band.

A Balanced Filtering Quasi-Yagi Antenna With Low Cross-Polarization Levels and High Common-Mode Suppression

Abstract: A balanced planar quasi-Yagi antenna integrated with a bandpass filtering response is presented in this paper. The proposed balanced antenna consists of a balanced stepped-impedance microstrip-slotline transition structure, a driver dipole, a parasitic strip, and a bandpass filtering unit. A good differential-mode (DM) passband selectivity is formed by inserting a microstrip stub-loaded resonator (SLR) in the feed line of the quasi-Yagi antenna. This integration enables the antenna to achieve both compact size and high frequency selectivity. By controlling the dimensions of SLR, the central frequency and fractional bandwidth (FBW) can be easy to be adjusted. Meanwhile, the microstrip-slotline transition structure can achieve a good wideband common-mode (CM) suppression without affecting the DM ones, thus simplify the design procedure. The proposed antenna with low cross-polarization level and high CM rejection is found to be comparable to the conventional quasi-Yagi antenna. Furthermore, there are two radiation nulls on both sides of the passband to improve the selectivity effectively. In order to validate its practicability, the balanced antenna is designed and fabricated. The experimental results exhibit that the designed balanced filtering antenna features good filtering response, low cross-polarization level, and high CM rejection.

Design and analysis of dual band integrated hexagonal shaped microstrip UWB antenna

Abstract: In this paper, we proposed a hexagonal shaped microstrip ultra-wideband (UWB) antenna integrated with dual band applications. The antenna design consists of a hexagonal shape patch with two folded Capacitive Loaded Line Resonators (CLLRs) on the left edge of the patch antenna. This hexagonal structure is used to implement UWB applications (3.1-10.6 GHz). A rectangular ground , and two CLLR are also used on t he bottom of antenna to obtain the extra dual resonant frequency at 2.4 GHz and 9.1 GHz for B luetooth and radar applications respectively. The proposed design is implemented using FR4 epoxy substrate. The relative permittivity of the substrate is 4 .4. The overall size of designing antenna is 26 × 30 mm2 with 1.6 mm as thickness and fed by standard feed line of 50 Ω microstrip . The results obtained from the simulation indicate that the designed antenna attains a good bandwidth from 1.1 GHz – 10.69 GHz with VSWR < 2 and return loss < -10 dB. The proposed geometry is s imulated by using the Ansoft HFSS simulator working on the principle of FEM and results are also analyzed.

Enhancement gain of broadband elliptical microstrip patch array antenna with mutual coupling for wireless communication

Abstract: The paper is presented analysis, design and manufacturing single optimize parameters of a new broadband elliptical patch antenna with microstrip center feed line and the array has been implemented to improve gain antenna. The antenna array dimension of mm 3 and fabricated on an FR-4 epoxy substrate having relative dielectric constant =4.3, loss tangent tan (δ) =0.002 and the feed line used has characteristic impedance of 50Ω and added the triangle notch structure .Thus notch can achieve maximal additional enhancement impedance bandwidth are (3.679- 6.578) GHz, (13.84-25.142) GHz, (29.807-37.618) GHz and the gain 8dBi. The antenna array performance was modified by inserting stubs transition in feeding Microstrip line to reducing mutual coupling achieve impedance bandwidth (when S 11 -10dB). The modified antenna was designed to be used for wireless communication application. The simulation results are obtained using CST software.

Design of a Wideband L-Shape Fed Microstrip Patch Antenna Backed by Conductor Plane for Medical Body Area Network

Abstract: This paper describes a compact patch antenna intended for medical body area network. The antenna is fed using a proximity coupling scheme to support the antenna that radiates in the free space and on the human body at the 2.45 GHz ISM band. The conductor plane is placed 2 mm or 0.0163λ0 (λ0 is free space wavelength at 2.45 GHz) below the antenna to reduce backward radiation to the human body. Separation distance must be kept above 2 mm, otherwise, gain of the proposed antenna decreases when antenna is situated on the human body. The L-shape feed line is introduced to overcome impedance mismatch caused by the compact structure. The coupling gap between the proposed antenna and the length of the L-shape feed line are optimized to generate dual resonances mode for wide impedance bandwidth. Simulation results show that specific absorption rate (SAR) of the proposed antenna with L-shape feed line is lower than conventional patch antenna with direct microstrip feed line. The proposed antenna achieves impedance bandwidth of 120 MHz (4.89%) at the center frequency of 2.45 GHz. The maximum gain in the broadside direction is 6.2 dBi in simulation and 5.09 dBi in measurement for antenna in the free space. Wide impedance bandwidth and radiation patterns insensitive to the presence of human body are achieved, which meets the requirement of IoT-based wearable sensor.

Miniaturized triple band-notched quasi-self complementary fractal antenna with improved characteristics for UWB applications

Abstract: This paper is a continuation and extension of a previous work [1]. In this paper, an enhanced UWB microstrip-fed quasi self-complementary fractal (QSCF) antenna with triple band notches is presented. These band notches are allocated at 3.5, 5.5 and 7.8 GHz. The proposed design supports coexistence with narrow band applications IEEE 802.16 WiMAX, IEEE 802.11 WLAN and X-band of satellite communications, respectively. Both slot and parasitic loading techniques are utilized to achieve this goal. A guided half wavelength U-shape slot is etched in the ground for creating band rejection at the WiMAX frequency band. To attain the WLAN band rejection, another half wavelength U-shape slot is inserted to the feed line. A split ring resonator (SRR) is embedded to the left and right of the feed line for avoiding interference with X-band. The prospective antenna is designed using low cost FR4 substrate of miniaturized size 32 × 16.5 × 1.5 mm3 which empowers it to be embedded in assorted portable devices. Nearly omnidirectional radiation patterns and stable gain are accomplished over the operating bandwidth from 2 to 11 GHz. For further clarification of the operating principle, an equivalent circuit model is considered showing good agreement with CSTMWS, HFSS and experimental results. Furthermore, a time domain analysis is investigated presenting satisfactory distortion performance between excited and received pulse validating it for diversified UWB applications.

Hexagonal Patch Antenna with Triple Band Rejections

Abstract: In this paper, a new planar hexagonal shaped antenna with triple band rejections is presented. The hexagonal patch is designed on FR4-substrate, having circular cuts at its vertices and fed by $50 \Omega $ micro-strip triangular tapered feed line. This antenna with a partial ground plane and five half circular sleeves achieves a 26.15 GHz bandwidth (with return loss $\geq 10$ dB). Triple-frequency band rejections are achieved by adding an inverted E-shaped stub in addition to two triangular slots in the patch and square slot with a parasitic square inside. The proposed antenna is investigated using the high-frequency structure simulator (HFSS). The simulated scattering parameter S11 (Reflection Coefficient) results show three band rejections (1.66. – 3.29), (4.72 - 5.81) and (7.86 - 8.62) GHz to reject the unwanted interference from several applications as WiMAX and satellite communications. A small value of gain at the rejection bands with good radiation patterns in E-plane and H-plane are achieved.

A circularly polarized wide-band magneto-electric dipole antenna with simple structure for BTS applications

Abstract: A circularly polarized magneto-electric dipole antenna with wide frequency band for base transceiver station (BTS) is presented. The structure of the proposed antenna is composed of a cavity metallic reflector with defected side walls, two pairs of vertical and trapezoidal horizontal copper plates and a Г-shaped feed line. Defected side walls of the metallic reflector are utilized to improve the gain, front to back ratio (FBR) and impedance matching. Electric dipole and quasi magnetic dipole are realized with horizontal plates and shorted vertical plates, respectively. The trapezoidal horizontal plates are employed to obtain circular polarization (CP) characteristic with 3-dB axial ratio bandwidth of 41% from 1.7 to 2.6 GHz. Experimental results show that the proposed antenna operates at frequency range of 1.4–2.8 GHz with S11

A compact coplanar waveguide feed bow-tie slot antenna for WIMAX, C and X band applications

Abstract: In this paper, a planar bow-tie slot antenna with coplanar waveguide fed for tri-band i.e. WIMAX, C and X band wireless communication applications is proposed. This antenna has been designed to meet the prerequisite of multiple resonant frequencies by setting up the proper dimensions of the bow-tie arm slots and feed line cutout slots. The dimensions corresponds to the tri-band resonant frequencies, are obtained by engraving slots of distinct length and width above the ground plane. The antenna is fed by 50Ω coplanar waveguide feed line. Physical size of the proposed antenna is 30×60 mm2 designed on thick substrate. The copper cladding ArlonCuClad217(tm) woven fiberglass laminate material with dielectric loss tangent 0.0009 and relative permittivity 2.17 is used. The gain, impedance bandwidths, return loss, and VSWR of proposed antenna has been analyzed and discussed. Moreover, the extensive parametric study has been carried out with the dimensions of feed line cutout. The simulation results have shown that the designed prototype of an antenna exhibits the peak realized gain of 6.9dBi and average gain of 2.3dBi.The proposed antenna has three operating bands, which are suitable for WIMAX, C-band and X-band applications.

Small New Wearable Antennas for IOT, Medical and Sport Applications

Abstract: Efficient small antennas are crucial in the development of wearable wireless communications and medical systems. Low efficiency is the major disadvantage of small antennas. Meta material and fractal technology are used to improve the efficiency bandwidth of small antennas. Moreover, the dynamic range and the efficiency of communication system may be improved by using active wearable antennas. Amplifiers may be connected to the wearable antenna feed line to increase the system dynamic range. Novel wideband passive and active efficient wearable antennas for IOT, BAN and 5G applications are presented in this paper. The gain and directivity of the patch antenna with Split-ring resonators, SRR, is higher by 2.5dB than the patch antenna without SRR. The resonant frequency of the antennas with SRR is lower by 5% to 10% than the antennas without SRR. Active small wearable antennas may be used in receiving or transmitting communication, IOT and medical systems. For example, the active slot antenna gain is 12±2dB for frequencies from 1.25GHz to 3.25GHz. The active slot antenna Noise Figure is 0.6±0.2dB for frequencies ranging from 1GHz to 3.3GHz.

An SISL Triple-Band Multimode Stacked-Patch Antenna With L-Strips for Multiband Applications

Abstract: A substrate-integrated suspended line triple-band multimode antenna with stacked patch and two L-strips is presented for multiband applications. The two L-strips connected the stacked patch by vias, which can be regarded as a modified step impedance resonator, are introduced for producing two resonant frequencies at 2.45 and 3.6 GHz by means of stimulating dual modes. The two resonant frequencies rely on not only the electrical length but also the impedance ratio. In the higher frequency band, resonant frequencies at 6.1 and 5.25 GHz are generated by the stacked patch and via which connects the feed line and the driven patch, respectively. The measured results reveal that the first band from 2.4 to 2.45 GHz with gain of 4.9 dBi, the second band from 3.52 to 3.6 GHz with gain of 6.2 dBi, and the third band from 5.12 to 6.18 GHz with gain of 10 dBi are acquired. In addition, the radiation patterns with stable property across the whole operating band are obtained.

Bandwidth Improvement of Center-Fed Series Antenna Array Targeting for Base Stations in Offshore 5G Communications

Abstract: A $1\times 12$ center-fed series antenna array, with a novel probe feeding structure to broaden the bandwidth, is designed for 5G base stations deployed in the land for offshore maritime communications. The improvement of the bandwidth is achieved through a combination of folding and replacing the center feed line to a lower layer away from patch radiators. By moving the center feed line to the lower layer beneath radiators, serious mutual-coupling and corresponding parasitic effect between the feed and radiators are reduced, facilitating better transmission and also resulting in better matching to the 50- $\Omega $ coaxial probe. Moreover, a vertically folded-U structure is proposed to be inserted in part of the feed line, to provide a section of a high impedance microstrip line and further broaden the impedance bandwidth. A simulation study is performed on the geometry of the center feed line to investigate how the antenna performance can be controlled. The antenna array design procedure is outlined and a prototype with over 20% bandwidth, which can fully cover the 4.8–4.99 GHz 5G spectrum band, is fabricated and measured for impedance matching, radiation pattern, and broadside gain. For both S-parameter and far-field results, good correspondence is achieved between simulation and measurement. The proposed series-fed antenna array with coaxial feed is very suitable to be deployed in base stations with 1-D beam steering capability.

Analysis and optimisation of super-wideband monopole antenna with tri-band notch using a transmission line model

Abstract: A study of monopole antenna for super-wideband applications is presented. A compact patch antenna is suggested to enhance the overall covered bandwidth (BW), where a major improvement of the BW obtained in the range 2.6-23 GHz (BW of 20.4 GHz). Also, by creating slots in the patch and in the feed line; three band-notches are created to reject different narrowband applications. The different antenna parameters are studied using a high-frequency structure simulator (HFSS). The measured data of the fabricated antenna shows good agreement with the simulated results with a slight shift at the lower and upper edges of the frequency range. A transmission line model of the proposed antenna is presented based on the effect of each element on the antenna behaviour. Advanced design system is used to construct and optimise the equivalent circuit model of the designed antenna. Results of the antenna behaviour obtained using the resistor-inductor-capacitor model compare favourably with the simulated results obtained using the HFSS both in the pass and rejection bands, with a small error at high frequencies.

Holistic Appraisal of Modeling Installed Antennas for Aerospace Applications

Abstract: This paper uses the unstructured transmission line modeling method to investigate near-field interactions between a broadband microwave antenna and a platform that arise as a result of antenna installation. The antenna, feed line, and the platform are represented by a common meshed model and simulated using a single time-domain numerical method. This paper aims to establish guidelines on how to achieve high accuracy when modeling both the near and far fields of an antenna while at the same time prioritizing computational resources. By isolating critical features such as the feed line and selected fine details of the antenna geometry, this paper assesses how accurately these fine features need to be described in the model and how they affect the return loss and far-field pattern of the antenna. The size of the platform is varied from small to medium size (up to 10 wavelengths) and its impact on the antenna performance is assessed. Finally, the conclusions of the study are applied to an example of an antenna installed in the leading edge of an aircraft wing, with and without, a protective radome cover.

Radiation enhancement for a triband microstrip antenna using an AMC reflector characterized with three zero-phases in reflection coefficient

Abstract: A compact tricyclic nested triband microstrip antenna is designed in this paper, which is composed of three metal rectangular rings, an input feed line, and an elliptic-shaped defected grou...

Electrically Small Water-Based Hemispherical Dielectric Resonator Antenna

Abstract: Recently, water has been proposed as an interesting candidate for use in applications such as tunable microwave metamaterials and dielectric resonator antennas due to its high and temperature-dependent permittivity. In the present work, we considered an electrically small water-based dielectric resonator antenna made of a short monopole encapsulated by a hemispherical water cavity. The fundamental dipole resonances supported by the water cavity were used to match the short monopole to its feed line as well as the surrounding free space. Specifically, a magnetic (electric) dipole resonance was exploited for antenna designs with a total efficiency of 29.5% (15.6%) and a reflection coefficient of −24.1 dB (−10.9 dB) at 300 MHz. The dipole resonances were effectively excited with different monopole lengths and positions as well as different cavity sizes or different frequencies in the same cavity. The overall size of the optimum design was 18 times smaller than the free-space wavelength, representing the smallest water-based antenna to date. A prototype antenna was characterized, with an excellent agreement achieved between the numerical and experimental results. The proposed water-based antennas may serve as cheap and easy-to-fabricate tunable alternatives for use in very high frequency (VHF) and the low end of ultrahigh frequency (UHF) bands for a great variety of applications.

Dual Band Rejected Low Profile Planar Monopole Antenna for UWB Application

Abstract: In this paper, a new design of ultra-wideband band (UWB) antenna with dual band rejection characteristics and sizeminiaturization approach has been presented. The proposed antenna consists of unique patch of trapezoidal shape, 50 Ω impedance triple down step microstrip feed line (on top plane) and partial ground plane (on bottom plane). The patch tapering results to bandwidth (BW) improvement. It works efficiently over the impedance bandwidth of 3-13 GHz and gives Fractional Bandwidth (FBW) of 125% that covers the entire UWB band. It provides nearly omnidirectional radiation pattern, has good realized gain and impedance matching. A triple step feed increases electrical length of patch, which leads to antenna size miniaturization. Therefore, the proposed antenna has been designed with dimensions of 22 mm × 28 mm × 1.6 mm, dielectric constant (Ɛr) of 4.4 and tangent loss of 0.02. For wireless applications, some specific UWB systems suffer from strong narrowband interference of unlicensed (ISM band) wireless communication devices. To avoid this unwanted interference, band rejection characteristics should be inserted into the antenna patch structure. The proposed antenna has designed with dualband rejection capability that efficiently avoids Wi-MAX and WLAN interference. The V-slot is etched on patch radiator to reject Wi-Max (3.15–4 GHz) and single C-strip pair besides feed line is used to reject WLAN (5.18-5.95 GHz) band. The output performance has measured in terms of simulated reflection coefficient and VSWR.

Folded aperture coupled patch antenna fabricated on FPC with vertically polarised end-fire radiation for fifth-generation millimetre-wave massive MIMO systems

Abstract: The authors proposed a folded aperture-coupled patch antenna (ACPA) on a flexible printed circuit (FPC) with vertically polarised end-fire radiation, suitable for fifth-generation millimetre-wave massive multi-input-multi-output (MIMO) systems. For low-cost implementation, antenna elements were fabricated on a single polyimide substrate. The fabricated FPC was first folded to implement a three-layer ACPA, and then the feed line was bent 90° to achieve end-fire radiation. Measurement of five antenna samples demonstrates that the resonance frequency lies between 27.7 and 28.3 GHz. Each antenna sample has the bandwidth (| S 11 | 1.2 GHz. The measured antenna gain is 2.74 dBi at 28.1 GHz, and the difference between co- and cross-polarised radiation intensities is >15 dB in all directions of interest. To improve the impedance bandwidth and the gain further, they increased the distance between the patch and the aperture of the proposed antenna by folding the fabricated FPC multiple times without an additional layer. Experimental results confirm the bandwidth of 2.64 GHz (26.27-28.91 GHz) and the gain of 3.80 dBi at 28 GHz. Additionally, the 1 × 8-folded APCA array is simulated to verify the feasibility for a practical application of multi-beam massive MIMO technology.

A Compact Ultra-Wideband Patch Antenna with Dual Band-Notch Performance for WiMAX / WLAN Services

Abstract: This paper presents a compact size ultra-wideband (UWB) patch antenna operating over frequency range of 3.02-13.84 GHz and has dual-band notched characteristics for WiMAX and WLAN wireless narrow-band applications. The designed antenna has a monopole nature constructed on a FR4-epoxy substrate with a microstrip transmission line feed style and has a partial ground plane configuration. For developing a dual-band notch performance, a mirror L-shaped connected together from the top has been etched near to the feed line terminal connected to the patch for suppressing the WiMAX operating band. Furthermore, a spilt ring resonator (SRR) slot configuration has been notched on the lower part of the patch for eliminating the WLAN frequency band. The proposed antenna has been designed using CST-EM software package. All the dimensions introduced in the proposed antenna have been optimized to obtain the proper antenna performance. The antenna characteristics have been investigated in terms of the impedance bandwidth, surface current distribution, maximum gain, radiation efficiency, and radiation pattern. The simulation results demonstrate that the antenna has good performance for UWB services.

On the Design of Effective EBG Structures to Model Highly Efficient Rectangular Patch Antenna for Wireless Applications

Abstract: The paper deals with relative analysis of radiation parameters of various rectangular patch antennas with quarter wave feed line. Star shaped and fan shaped Electromagnetic Band Gap (EBG) are incorporated separately on base plane of each antenna. Resonant frequency apprehended for the designed antennas is 5.25 GHz. The proposed fan shaped EBG based antenna exhibits a wide bandwidth of 244 MHz covering wireless applications like IEEE 802.11a Wireless Local Area Network (WLAN) (5.125–5.395 GHz) and High Performance Local Area Network type 1 (HIPERLAN/1) (5.150 GHz– 5.350 GHz). The antenna also covers a well portion of Worldwide interoperability for Microwave Access (Wi-MAX) (5.25-5.85GHz) with comparatively healthy gain of 7.15 dB and noteworthy radiation efficiency. Size reduction of patch with the installation of EBG structures has also been brought forward in this work. The design and simulation has been carried out using FDTD method based transient solver of CST MWS software.

Design and Implementation of a Multiband Quasi-Yagi Antenna

Abstract: in this paper, a coplanar waveguide-fed planar monopole antenna for multiband operations is presented. The antenna consisting of a multistrip quasi-yagi element and a coplanar waveguide to coplanar slot fed line, and the electric fields at the coplanar slot line can be excited through the CPW feed line. The proposed antenna can be used in multiband operations with directional radiation patterns. It generate four resonant frequency bands determined by -10dB reflection coefficient, it can cover number useful wireless communication systems; the structure plan of the antenna facilitates its integration with the other circuit components.

Movable short-circuit technique to extract the relative permittivity of materials from a coaxial cell

Abstract: In recent years, industrial applications have been based on the use of intrinsic material properties that improve designs, processes, qualities and product controls. To get to those intrinsic parameters, various appropriate techniques are required. In this paper, a new technique has been developed and presented. It essentially puts the emphasis on the dielectric relative permittivity extraction from the principle of a movable short-circuit through the coaxial transmission-line cell. This technique is aimed at drastically reducing the discontinuity impacts at the interface feed line (connector) and ideal line, solving the phase constant frequency limit, stopping the constraints bound to the higher mode propagations and improving the accuracy level when the frequency range has increased. The technique is based on the use of the sum of two different lengths of the cell by removing the first value of the phase constant in the frequency range of interest when it is negative. This new technique can be easily implemented; its focus is not on iterative principles, but on the use of the constant propagation of a Quasi-TEM mode of the transmission-line. The bio-food industry (semolina), environmental field (palm tree) and building trade (aquarium sand) were used to test the validity of the technique in 2-20 GHz.

Design of compact single-ended-to-balanced filtering power divider with wideband common-mode suppression

Abstract: A new design of single-ended-to-balanced (SETB) filtering power divider (FPD) with wideband common-mode (CM) suppression is presented. To effectively realise high suppression of CM noise, a hybrid structure constructed by both the double-side parallel-strip line (DSPSL) and a half-mode defected ground structure (HMDGS) serving as the mid-inserted conductor plane are adopted. Besides, due to the effect of HMDGS, the rejection of second harmonics for the differential-mode (DM) transmission is also improved. Meanwhile, by employing two pairs of dual-mode resonators symmetrically coupled with a stepped-impedance input feed line and adding a DSPSL stub, wideband-filtering performance with high selectivity is achieved. For validation, a prototype of the proposed SETB-FPD centred at 5.9 GHz with a 3-dB fractional bandwidth (FBW) of 27% is designed, fabricated and measured. Results indicate that the proposed SETB FPD exhibits good performances of high selectivity, wide upper stop band, good isolation between two balanced output ports and 30-dB suppression of CM noise over the DM pass band.