Showing papers on "Front-to-back ratio published in 2017"

An Azimuth-Pattern-Reconfigurable Antenna With Enhanced Gain and Front-to-Back Ratio

Abstract: This letter presents a novel gain-enhanced pattern reconfigurable antenna. The proposed antenna consists of a windmill-shaped reconfigurable feeding network, four Vivaldi-shaped slots, and four groups of reconfigurable artificial structures. By electrically controlling the p-i-n diodes integrated in the feeding network and in the artificial surface, four endfire radiation patterns with enhanced gain and front-to-back ratio (FBR) are realized. The antenna is simulated and measured. Measured results show that, with the loaded reconfigurable artificial surface, a gain enhancement of 1.0-3.5 dB and an FBR improvement of 4.5-8.2 dB over a wide band of 5.35-6.45 GHz are obtained.

A Single Layer Semi-Ring Slot Yagi-Like MIMO Antenna System With High Front-to-Back Ratio

Abstract: A novel two-element single layer semiring slot-based Yagi-like multiple-input-multiple-output (MIMO) antenna system with a compact complementary slot reflector element is presented. This antenna system covers the 3.5 GHz band for WiMAX applications. It has a minimum measured bandwidth of 320 MHz covering from 3.48-3.8 GHz. A simple and compact slot reflector element having the size of 14 x 9.5 mm 2 is used to achieve a minimum measured front-to-back ratio of 10 dB without using additional metallic layers, reflector elements, or any complex back-lobe reduction technique. The total board size of the MIMO antenna system is 80 x 40 x 0.8 mm 3 while the single antenna element has a size of 40 x 40 x 0.8 mm 3 . The antenna system is fabricated and tested. Good agreement is found between simulated and measured results. A measured realized gain of 4.3 dBi, directivity of 6 dB and a minimum measured total radiation efficiency of 73% across the entire band of operation were achieved. This MIMO antenna system has minimum measured isolation of 12 dB, maximum measured envelope correlation value of 0.0385 and diversity gain of 9.81 dB across the entire band of operation.

A Mode-Superposed Microstrip Patch Antenna and Its Yagi Array With High Front-to-Back Ratio

Abstract: A new microstrip patch antenna with a linear superposition of its even and odd modes is proposed for a high front-to-back (F/B) ratio. With the mode superposition, the patch antenna has its main beam in the forward quadrant space and an inherent high F/B ratio. The antenna exhibits a vertical polarization in the ground plane. With a low profile, the patch antenna generates a wide impedance bandwidth though a relatively narrow radiation bandwidth (F/B > 15 dB). In order to have a wider radiation bandwidth with a high F/B ratio, a vertically polarized Yagi array antenna is constructed based on the patch antenna, with an electromagnetic band gap (EBG) structure as a reflector and a quarter-wavelength patch antenna as a director. (The employment of the EBG structure is helpful for the enhancement of the F/B ratio, but it increases the array size on the other hand.) Measured results show that the constructed Yagi array antenna with a low profile of 0.025 $\lambda_{0}$ achieves an impedance bandwidth of 11.5% (4.83–5.42 GHz) for $\vert {S}_{{11}} \vert$ < −10 dB. Moreover, it has a wide radiation bandwidth of 10.1% (4.90–5.42 GHz), in which the F/B ratio is higher than 15 dB and the gain is from 8.5 to 9.5 dBi.

Compact, wideband-printed quasi-Yagi antenna using spiral metamaterial resonators

Abstract: A novel structure for size reduction and bandwidth enhancement of quasi-Yagi antenna using spiral resonator (SR) metamaterials is presented. The basic resonance is produced through excitation of simple quasi-Yagi antenna elements through a microstrip feedline while parasitic SR metamaterials augment bandwidth. The antenna is designed on an glass-reinforced epoxy laminate sheets (FR4) substrate with a dielectric constant of 4.4 and a thickness of 1.6 mm. Compared to original printed quasi-Yagi antennas, the size of the proposed quasi-Yagi antenna is reduced by ∼53%. Simulation results show that the proposed antenna has the impedance characteristics with a frequency bandwidth of 1.43–3.97 GHz (94%) for return loss more than 10 dB and a gain of 3.4–5.2 dBi in the corresponding frequency range. The designed antenna presents an end-fire radiation with a front-to-back ratio >10 dB. The antenna is fabricated, and measurement results demonstrate compactness and wide bandwidth of the antenna.

Front to Back Ratio Bandwidth Enhancement of Resonance Based Reflector Antenna by Using a Ring-Shape Director and Its Time-Domain Analysis

Abstract: An uni-directional antenna designed by resonance-based reflector has the merits of compact size, low-profile, and ultra-wide impedance bandwidth. However, its front to back ratio (FBR) bandwidth is narrow owing to the small reflection coefficient values at the high frequencies of the RBR in-phase band. To solve this problem, a ring-shaped director (RD) was placed above a resonance-based reflector-based antenna to guide the high frequencies. Then, the FBR bandwidth was enhanced. The proposed antenna achieves a wide measured impedance bandwidth from 2.17 to 3.76 GHz (53.6%). Its FBR band (FBR >7 dB) covers the whole operational band and the FBR >10-dB band covers 2.17–2.58 GHz (17.3%). The proposed antenna consists of a bow-tie element, a ring-shaped resonance-based reflector under the bow-tie element and an RD above the bow-tie element to form a sandwich configuration. The profile of the proposed antenna is only $0.16~\lambda $ at the lowest frequency of 2.17 GHz. To further evaluate the performances of the proposed antenna, the time-domain characteristics of the antenna were analyzed in terms of group delay, waveform response, correlation coefficient, and pulsewidth stretch ratio. Good time-domain characteristics were observed.

Tunable Terahertz Filter-Integrated Quasi-Yagi Antenna Based on Graphene

Abstract: In this paper, a filter-integrated quasi-Yagi antenna (FIQYA) with quasi-independently tunable passband and front-to-back ratio is proposed by using graphene. The graphene at two ends of the coupled-line ring resonator mainly affects the impedance bandwidth while the front-to-back ratio of radiation patterns is attributed to the graphene-implanted open-circuited director. The bandwidth and front-to-back ratio tunability is accomplished by altering the complex conductivity of graphene controlled by chemical potential. For verification, a 2-THz FIQYA using both perfect electric conductor (PEC) and graphene with two different controllable chemical potentials (μ c1 and μ c2) is simulated. The simulated results show that the maximum tunable impedance bandwidth of the FIQYA is varied from 186 to 235 GHz without affecting the radiation patterns when μ c1 changes from 0 to 0.2 eV. The maximum tunable front-to-back ratio is changed from 11.7 to 15.4 dB while μ c2 is altering from 0 to 0.6 eV, maintaining an acceptable matching bandwidth in all cases.

An axial-ratio beam-width enhancement of patch-slot antenna based on EBG

Abstract: A low-profile axial-ratio beam-width enhancement of patch-slot antenna based on electromagnetic band gap (EBG) structure is proposed. To achieve the circularly polarized property, a diagonal slot is etched in the center of the radiation patch. The traditional mushroom-like EBG unit cells around the patch are used to suppress the surface wave and improve the front to back ratio. This proposed antenna is printed on the FR4 substrate and fed by a single, conventional coaxial cable with 50 Ω impedance. Measured results show that the impedance bandwidth and 3-dB axial ratio bandwidth of proposed antenna are 128 and 30 MHz, respectively. By using EBG unit cells, the 3-dB AR beam-width can be extended to 232.5° at x–z plane and 258° at y–z plane. The front to back ratio of the antenna is also improved to 25 dB. © 2017 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:493–497, 2017

Low-Profile Dual-Polarized Planar Antenna with Compact Structure for Base Stations

Abstract: A low-profile dual-polarized planar antenna with compact structure for 2.4GHz Wireless local area network (WLAN) and 2.5GHz Long term evaluation (LTE2500) base stations is proposed. A combination of a planar radiator and compact Artificial magnetic conductor (AMC) reflector is utilized to achieve a full planar structure without adding extra matching circuit, an extremely low-profile of 0.127 wavelength, as well as a high front to back ratio (F/B) of 25dB. The antenna is fabricated to test the performance such as S-parameters, radiation patterns and peak gain. Reasonable results show the suitability of the proposed antenna for 2.4GHz WLAN and LTE2500 applications.

On Q-factor bounds for a given front-to-back ratio

Abstract: In this paper, the goal is to solve an antenna current optimization problem minimizing the stored energy with a desired front-to-back ratio. This minimization problem is non-convex, and we use semidefinite relaxation techniques to find the solution. An initial study on the front-to-back ratio of a dipole shape is presented here.

Front-to-back ratio improvement of a microstrip patch antenna by using co-planar rod parasitic elements for 1.8 GHz wireless applications

Abstract: This study presents a novel, simple technique to improve the Front-To-Back Ratio (FTBR) of a microstrip patch antenna. The radiation in the backward direction of the microstrip patch antenna is reduced by introducing two rod shaped parasitic elements on either side of the patch antenna, designed for 1.77GHz. The simulation results obtained, by using CST Microwave Studio 2016, show that the back lobe can be reduced by more than 15dB, over and above the plain microstrip antenna. The return loss also gets reduced. Half Power Beamwidth (HPBW), bandwidth and antenna efficiency are also increased.

All-band GNSS antenna with artificial magnetic conductor

Abstract: With the introduction of multiple GNSS service providers, antennas that cover all GNSS bands become especially important. All-band GNSS antenna must cover 1146 MHz-1610 MHz band, have high front to back ratio, and good axial ratio with large beamwidth for better satellite coverage. Although many antenna topologies exist for broadband operation, circularly polarized (CP) broadband antennas that simultaneously have impedance and axial ratio wide bandwidths are scarce. Especially for GNSS applications, antenna performance can be demanding depending on the application and limited space provided for the antenna. To overcome these shortcomings, crossed pie-shaped printed dipole antenna with artificial magnetic conductor (AMC) reflector is proposed. We also propose a unique feed structure that does not utilize hybrid coupler and provide wideband operation for the target frequency band. The proposed antenna is realized and measurement results are corroborated with simulations.

Wide-beam circularly polarized microstrip antenna with high front-to-back ratio for CNSS application

Abstract: A novel circularly polarized (CP) microstrip antenna with wide beam and high front-to-back ratio is proposed for compass navigation satellite system (CNSS) application. Based on the single-fed patch antenna, parasitic strips are loaded on the same layer to broad the beamwidth. Reactive impedance structure (RIS) is designed as a reflector to obtain a high front-to-back ratio. More importantly, good circularly polarized performance can be obtained in a wider range of beamwidth by adjusting reflection phase. Experimental results show that the measured half-power (HP) beamwidth is approximately 147° and the 3dB axial-ratio (AR) beamwidth is more than 180°. A front-to-back ratio of 20 dB can be achieved within the bandwidth.

Mode superposition microstrip yagi antenna with high front-to-back ratio

Abstract: The invention provides a mode superposition microstrip yagi antenna with a high front-to-back ratio The antenna comprises a medium board, an upper metal radiator, a metal floor, a short circuit nail and a feed connector, wherein the upper metal radiator is at one side of the medium board, the metal floor is at the other side of the medium board, the short circuit nail penetrates through the medium board to connect the upper metal radiator with the metal floor, a center feed needle of the feed connector is connected with the upper metal radiator, and an external conductor of the feed connector is connected with the metal floor The mode superposition method is utilized to generate end emission wave beams having the high front-to-back ratio, an electromagnetic band gap structure further added as a reflector and a quarter-wave antenna added as a director form a microstrip yagi antenna, the front-to-back ratio of the antenna within the work frequency band and gain are further improved, radiation bandwidth is expanded, the front-to-back ratio is higher than 15 dB, moreover, the director is further utilized to compensate impedance, the frequency band of the antenna is widened to a maximum degree, and broadband characteristics are realized

Two element microstrip antenna array using square slot EBG structure for C-band applications

Abstract: This paper discusses the performance of two element microstrip antenna array (TMA) in the absence and presence of square slot 2D-Electromagnetic Band Gap (EBG) structure. The antenna arrays have been designed using Mentor Graphics IE3D simulation software and measured results obtained using vector network analyzer. The antenna arrays have been fabricated using FR-4 glass epoxy substrate. The proposed antenna array operates in the C-band ranging from 4–8 GHz. The TMA designed at 6 GHz resonates at 5.445 GHz with a bandwidth of 197 MHz. With the EBG structure loaded in the ground plane of TMA, the antenna array shows enhanced performance in terms of bandwidth, mutual coupling, miniaturization, back lobe radiation and front to back ratio.

Method for monitoring electrical performance parameters of base station antenna

Abstract: The invention discloses a method for monitoring electrical performance parameters of a base station antenna The method comprises the following steps: adopting an HackRF One hardware platform to receive electromagnetic waves emitted by the base station antenna, and performing intermediate frequency processing and digital processing on the electromagnetic waves; transmitting processed data to an Android system terminal, and performing digital filtering processing and FFT processing on the data, and obtaining spectral analysis; and finally finishing extraction of the electrical performance parameters according to the spectral analysis, wherein the electrical performance parameters comprise the half-power beam width, side lobe level, front to back ratio, directivity factor, and antenna gain The method for monitoring the electrical performance parameters of the base station antenna provided by the invention optimizes the accuracy of a traditional extraction method of the electrical performance parameters; and the monitoring method is helpful to help the base station maintenance personnel to maintain antenna equipment, optimize the network, and improve the stability and reliability of interactive data between a mobile terminal user and a base station

High front -to -back ratio base station antenna reflecting plate

Abstract: The utility model relates to a mobile communication field, more specifically relates to a high front -to -back ratio base station antenna reflecting plate, this high front -to -back ratio base station antenna reflecting plate, including reflection face (1), the setting is at the left and right sides curb plate (2) of reflection face both sides, the setting is at the cavity structures of reflecting plate downside, the setting is in metal sheet extension structure (4) in the cavity structures bottom outside, reflection face (1), left and right sides curb plate (2), cavity structures and metal sheet extension structure (4) mutual formula structure as an organic whole, the utility model discloses a high front -to -back ratio base station antenna reflecting plate through the setting of controlling curb plate, cavity structures and metal sheet extension structure, makes high front -to -back ratio base station antenna reflecting plate have outstanding front -to -back ratio, and this antenna design is more succinct, has reduced the assembly, and the cost is practiced thrift in the production of being convenient for.

Directive orthogonal polarized superwideband isolated MIMO antenna with small group delay and large front to back ratio

Abstract: This paper proposes a simple multiple input multiple output (MIMO) microstrip patch antenna for superwideband applications. The antenna has percentage bandwidth of 182.17% for superwideband (14–300)GHz and also supports two significant frequency bands having bandwidth of 2.35GHz (0.1–2.45GHz) and 2.1GHz (7.2–9.3GHz). For all frequencies the antenna input impedance is matched with 50 Ω coplanar waveguide feeding. The antenna is simulated using CST Microwave Studio software. −30dB isolation between MIMO ports and the envelope correlation coefficient value is below 0.1 makes the antenna an ideal candidate of MIMO superwideband antenna. Furthermore 53dB front to back ratio and 33dB directivity with more than 88% radiation efficiency is found in simulation result. Integration of this antenna with microwave integrated circuits is also possible. Design details and results are presented.

Circularly-polarised slot array with high front-to-back ratio and low axial ratio

Abstract: A novel design for circularly-polarised (CP) arrays is proposed. The proposed array is composed of dual CP slot antenna elements arranged in a face-to-face configuration, and they are simultaneously excited through a slot line. By properly controlling the excitation amplitudes and phases of the two radiating elements, the cross polarisation and back radiation of the array can be effectively reduced. From the measured results, the proposed array can give an axial ratio of lower than 1 dB and a front-to-back ratio of higher than 12 dB within a 10 dB-return-loss bandwidth of >16%. Simulation results obtained with high frequency structure simulator (HFSS) also agree well with the experimental data.

A 8.7 Ghz Antenna Array based on New Feeding Technique of SIW

Abstract: In this paper, SIW based antenna array are proposed ,a new concept of feeding technique is adopted to implement a slot antenna array .There are four radiating slots cut on patch for radiating antenna.In this all slots are cut symmetrically.A H slot cut on centre of patch. By feeding technique, we excite H slot by which four slots are excited.By this technique we improve bandwidth ranging from 8.09 Ghz to 8.9 Ghz (9.31%)and front to back ratio is approx. 17 dB and peak gain is better than 4 dB.

Jamming propagation characteristics of a 4 × 4 array synthesis horn antenna using a high-power magnetron source

Abstract: In this paper, we analyzed the jamming propagation characteristics of a 4 × 4 array synthesis horn antenna by connecting a high-power magnetron source to it. The short-stub structures were attached to the upper and lower aperture of the proposed antenna to suppress a back lobe of the high-power energy. The antenna has a front to back ratio (FBR) of 39.4 dB and a 25 dB gain at a center frequency of 2.45 GHz. The waveguide adapter was designed to minimize the output loss in order to connect a high-power magnetron to the source, and the S21 was −0.31 dB. Finally, by connecting four high-power magnetron sources to the antenna, we confirmed that the drone flying at a distance of 10 m was jammed.