Design,analysis, and modeling of miniaturized multi‐band patch arrays using mushroom‐type electromagnetic band gap structures

Novel designs of miniaturized multi‐band 1 × 2 patch antenna array with electromagnetic band gap (EBG) for wideband operation are presented in this article. The proposed patch array is composed of three unequal arms fed by CPW‐to‐slotline transitions to widen the impedance bandwidth with multiple resonances. By adding two conventional mushroom‐type EBG (CMT‐EBG) structures on both sides of 100 Ω slotline transitions, the compact wideband patch array (first design) is obtained. This proposed design with CMT‐EBG includes two bands with the measured ranges (S₁₁ ≤ ?10 dB) of 6.65‐6.95 GHz (C‐band) and 8.57‐11.53 GHz (X‐band). Moreover, the proposed 1 × 2 patch array with the 3 × 3 CMT‐EBG array on the one side of the structure (second design) operates at multi‐bands with the measured ?10 dB impedance bandwidths of 5.80‐5.98 GHz, 6.25‐6.47 GHz, and 8.48‐11.52 GHz. The second design compared to the first design introduces a considerable size reduction with more resonance tuning capability. The performance of the proposed designs is analyzed based on the EBG band gap properties near the slotline transitions. These designs with the EBGs indicate prominent features like resonance tuning capability, acceptable miniaturization, and enhanced impedance bandwidth with low‐fabrication cost. In this study, an equivalent circuit model of the proposed first design with EBG is also offered to describe the properties of multi‐band operation.     

Design of dual‐band microstrip patch antenna with right‐angle triangular aperture slot for energy transfer application

This work focusing on the dual‐band antenna design with rectifying circuit for energy transfer system technology for enhancement gain performance. The air gap technique is applied on this microstrip antenna design work to enhance the antenna gain. The work begins with designing and analyzing the antenna via the CST Microwave Studio software. After validation on acceptable performance in simulation side is obtained, the return loss, S₁₁ of the antenna is measured using vector network analyzer equipment. The rectifier circuit is used to convert the captured signal to DC voltage. This projected dual‐band antenna has successfully accomplished the target on return loss of ?44.707 dB and ?32.163 dB at dual resonant frequencies for 1.8 GHz and 2.4 GHz, respectively. This proposed antenna design benefits in low cost fabrication and has achieved high gain of 6.31 dBi and 7.82 dBi for dual‐band functioning frequencies.     

Electromagnetic band‐gap structured printed antennas: A feature‐oriented survey

Wireless communication systems are playing an important role in different sectors of human society. Printed antennas are considered as the critical enabling technologies for these systems. The technology related to the design and development of printed antennas have been continuously improved from the structural view of configuration to antenna features improvement. Electromagnetic bandgap (EBG) structures have played a significant role in improving the features of printed antennas. In this paper, authors have restricted a feature–oriented comprehensive survey on EBG‐structured printed antennas. This type of survey is primarily required for the beginner working on EBG structures/EBG‐structured printed antennas. Such a survey process is rarely carried out in the open literature to the best of authors' knowledge. The proposed survey process is confined only to five different feature classifications; bandwidth improvement, gain improvement, dual‐band/multi‐band characteristics, band‐notch characteristics, and compact and low profile, respectively.     

A printed dual‐band dipole filtenna with flexible frequency ratio and improved band‐notched performance

A printed dual‐band dipole filtenna with flexible frequency ratio and improved band‐notched performance is proposed. It consists of a driven dipole and three parasitic elements. For the driven dipole with short and long arms, a radiation null is found between two passbands, which achieves a band‐notched filtering characteristic. Two parasitic elements are introduced to enhance the passband bandwidth and an additional parasitic element is utilized to improve the band‐notched performance. In addition, the characteristics of the proposed design including flexible frequency ratio, independent controllable operating frequency, and controllable band‐notched bandwidth have also been demonstrated. A filtenna prototype is fabricated and tested. Measured results show that a fractional bandwidth of 21.1% and 18.1% is obtained in the lower and upper passbands, respectively. The measured efficiency is 84% in the lower band and 74% in the upper band but the efficiency sharply decreases to about 13% within the notched band.     

Design of dual‐mode dual‐band rectangular waveguide filtering antenna

A dual‐mode dual‐band rectangular waveguide filtering antenna with fourth‐order Chebyshev response is presented. First, design equations and processes of filtering networks are presented. Then, filtering antenna is constructed through cross‐shaped slot for radiation instead of the output port of filtering networks. A pair of degenerated modes are exploited in waveguide resonator design to miniaturize the whole size and form two passbands. In addition, the bandwidth can be adjusted flexibly in proper range. A prototype at C‐band is fabricated and measured, showing two operation channels of 5 to 5.05 GHz and 5.1 to 5.15 GHz with high rejection between two bands. Good agreement is achieved between the simulations and measurements, showing excellent performance in terms of filtering, out‐of‐band rejection, and gain in bands.     

Novel dual‐band asymmetric U‐shaped slot antenna for dual‐circular polarization

A novel dual‐band, dual‐circularly polarized antenna is proposed and fabricated. The proposed antenna consists of an asymmetric U‐shaped slot and an inverted L‐shaped slot which are designed to excite two orthogonal E vectors with equal amplitude and 90° phase difference (PD), in addition, fed by a coplanar waveguide (CPW) Furthermore, a left‐hand circular polarization in the direction of z > 0 and a right‐hand circular polarization instead of the opposite direction both at the lower and upper bands are exhibited by the radiations of the antenna. Good agreement is achieved between the measurement and simulation, which indicates that a 10‐dB bandwidth of 38.75% from 2.56 to 3.8 GHz and 21.8% from 10.01 to 12.53 GHz, while a 3‐dB axial‐ratio bandwidth (ARBW) of 13.4% from 2.77 to 3.2 GHz and 9.23% from 10.25 to 11.25 GHz at two operation bands, respectively, are covered in the designed antenna. To explain the mechanism of dual‐band dual‐circular polarization, the analysis of magnetic fields distributions and a parametric study of the design are given. Meanwhile, compared to other recent works, a single layer structure, wider axial ratio and impedance bandwidths and a more compact size are the key features of the proposed antenna.     

A novel dual‐wideband inscribed hexagonal fractal slotted microstrip antenna for C‐ and X‐band applications

This paper presents a novel geometry of inscribed hexagonal slotted microstrip antenna for dual‐band performance where the fractal iteration has been made by introducing concentric slots in the patch geometry. Using the equivalence principle and cavity model, the basic geometry of the hexagonal slotted patch is analyzed, and the resonant frequencies of different modes of the patch are computed. Higher‐order modes of the patch antenna are used to obtain dual band. Good performance in terms of the reflection coefficient is proved with the help of parametric analysis. The antenna geometry is simulated using electromagnetic simulation software based on the finite‐element method. The prototype of this antenna is fabricated and tested. The practical results match with the simulated results. The proposed antenna provides improved average gain. The peak values of measured gain are found to be 5.238 and 7.023 dBi—in the two bands 5.85 to 6.48 GHz and 7.28 to 8.63 GHz, respectively. Stable radiation patterns with good average gain make the proposed antenna appropriate for long‐range transmission. Furthermore, low profile and low cost make this antenna suitable for the future point‐to‐point high‐speed wireless communication applications.     

Novel compact planar electromagnetic band‐gap structure using for ultra‐wideband simultaneous switching noise suppression

In this article, by analyzing the equivalent circuit mode for electromagnetic bandgap (EBG), a novel compact planar EBG structure is proposed for overcoming the drawback of narrow bandwidth of conventional EBG structures. The novel design is based on using meander lines to increase the effective inductance of EBG patches. The simulated and measured results demonstrate the simultaneous switching noise (SSN) can be mitigated with an ultra‐wideband from 280 MHz to 20 GHz at the restraining depth of ?40 dB. Compared with the traditional L‐bridge and meander lines EBG structures, this novel structure has the advantages of suppression bandwidth and fabrication cost. Moreover, signal integrity is achieved by the time‐domain simulation. The proposed structure provides a new kind of theoretical designing reference for EBG structure to improve the bandwidth of restraining SSN. © 2013 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:429–436, 2014.     

A compact dual‐band filtering antenna for wireless local area network applications

A printed dual‐band filtering antenna with decent frequency selectivity at 2.45 and 5.2 GHz for wireless local area network (WLAN) applications is developed. The filtering antenna is compact, which comprises a tapped feed line, two dual‐band stub‐loaded open‐loop resonators, and a dual‐band bended monopole. It can be easily printed on a single layer PCB substrate with low profile and low cost. The entire structure is very simple compared with the previously reported dual‐band filtering antennas that requiring multi‐layer structures. The monopole functions as not only a radiator, but also the last resonator of a dual‐band filter. The developed antenna exhibits good frequency selectivity and out‐of‐band suppression. In addition, the two operation bands can be adjusted relatively individually. The proposed antenna is optimized and fabricated. The experimental results show it has good frequency selectivity at both 2.45 and 5.2 GHz, wide bandwidth 11.8% and 7.8%, and excellent out‐of‐band suppression.     

Modeling of electromagnetic band gap structures: A review

This article represents a comprehensive review of the research carried out on analytical and numerical methods modeling of electromagnetic band‐gap (EBG) structures used in around last two decades. Because of the unique characteristics of the surface wave reduction as well as perfect magnetic conductor (PMC) like behavior, the EBG structures have created their separate existence in antenna engineering society. These structures are being widely used in designing of several microwave planar circuits including printed antennas, printed microwave filters, etc. The purpose of this article is to present an inclusive review of analytical methods as well as numerical methods in the context of modeling of EBG‐structures. Such a review process is rarely carried out in the open literature to the best of authors' knowledge. The review exercise might be helpful to the researchers working on modeling of EBG‐structures as well as of EBG‐structured printed antennas, microwave planar filters, etc.     

A compact dual‐band zeroth‐order resonator antenna loaded with meander line inductor

A novel zeroth‐order resonator (ZOR) meta‐material (MTM) antenna with dual‐band is suggested using compound right/left handed transmission line as MTM. In this article, suggested antenna consists of patch through series gap, two meander line inductors, and two circular stubs. The MTM antenna is compact in size which shows dual‐band properties with first band centered at 2.47 GHz (2.05‐2.89 GHz) and second band is centered at 5.9 GHz (3.70‐8.10 GHz) with impedance bandwidth of (S₁₁ < ? 10 dB) 34.69% and 72.45%, respectively. At ZOR mode (2.35 GHz), the suggested antenna has overall dimension of 0.197λ_o × 0.07λ_o × 0.011λ_o with gain of 1.65 dB for ZOR band and 3.35 dB for first positive order resonator band which covers the applications like Bluetooth (2.4 GHZ), TV/Radio/Data (3.700‐6.425 GHz), WLAN (5‐5.16 GHz), C band frequencies (5.15‐5.35, 5.47‐5.725, or 5.725‐5.875 GHz) and satellite communication (7.25‐7.9 GHz). The radiation patterns of suggested structure are steady during the operating band for which sample antenna has been fabricated and confirmed experimentally. It exhibits novel omnidirectional radiation characteristics in phi = 0° plane with lower cross‐polarization values.     

Investigation on dual‐port printed MIMO antenna with reduced RCS for C‐band radar application

In this communication, two port printed Multi Input Multi Output (MIMO) antenna with reduced radar cross section and low mutual coupling is designed and analyzed. Reduced mutual coupling (less than ?20 dB) is achieved by placing the electromagnetic band gap structure in between the two identical ports. Frequency selective surface has been used to reduce the radar cross section (more than 30 dB reduction) of the proposed antenna design, which makes it suitable for military applications. The proposed radiating design is fabricated and measured for the purpose of validation. It resonates at 6.8 GHz supporting an impedance bandwidth of 1.03 GHz from 6.12 to 7.15 GHz. It promises a gain of 4.75 dB in the working frequency range. This radiator is suitable for military radars works in C‐band.     

A dual‐band dual‐mode microstrip Yagi antenna with quasi‐end‐fire radiation

A dual‐band dual‐mode microstrip Yagi antenna with quasi‐end‐fire radiation patterns is proposed in this paper. It consists of five radiating patches driven by a single slot‐loaded patch placed in the middle. Meanwhile, two slot‐loaded parasitic patches are symmetrically located on two sides of the driven patch, respectively. In the lower band, the five patches involved resonate at TM₀₁ mode. While in the upper band, all the patches resonate at TM₀₂ mode. In order to ensure quasi‐end‐fire radiations in the both bands, four slots are symmetrically etched around the strongest surface currents of each patch resonating at TM₀₂ mode. As a result, the resonant frequency of TM₀₂ mode is decreased dramatically, while the resonant frequency of TM₀₁ mode almost remains unchanged. With these arrangements, the separations between any two of the adjacent patches at their centers satisfy the requirements in design of the microstrip Yagi antenna in both bands, so as to realize the dual‐band dual‐mode microstrip Yagi antenna on a single‐layer substrate. Finally, an antenna prototype is fabricated and tested. The measured results reveal that the dual operating bands of 2.76~2.88 and 4.88~5.03 GHz for |S₁₁| < ?10 dB are satisfactorily achieved. Most importantly, the proposed antenna can indeed realize the quasi‐end‐fire radiation patterns in dual operating bands.     

A dual‐band efficient circularly polarized rectenna for RF energy harvesting systems

A multilayered circularly polarized (CP), dual‐band, stacked slit‐/slotted‐patch antenna with compact size and with compact rectifier is offered for RF energy harvesting systems. The compact dual‐band CP antenna size is able to achieve by stacking slotted‐circular‐patch (SCP) on the substrate above the tapered‐slit‐octagon patch (TSOP). Dual‐band CP radiation is realized by stacking the SCP on the TSOP and the microstrip feedline with metallic‐via to SCP. Eight‐tapered‐slit with length difference of 6.25% are embedded along the octagonal directions symmetrically on the TSOP from the patch's center and two unequal size circular slots are embedded in diagonal axis onto SCP to produce dual‐orthogonal modes with almost equal magnitude for CP waves. The designed antenna is realized measured gain of greater than 5.2 dBic across the band (0.908‐0.922 GHz) with maximum gain of 5.41 dBic at 0.918 GHz and gain of greater than 6.14 dBic across the band (2.35‐2.50 GHz) with maximum gain of 7.94 dBic at 2.485 GHz. An overall antenna volume is 0.36λ _o × 0.36λ _o × 0.026λ _o (λ _o is free space wavelength at 0.9 GHz). A compact composite right‐/left‐handed (CRLH) based rectifier with dual‐band at 0.9 and 2.45 GHz is designed, prototyped, and measured. The right‐handed (RH) part of the CRLH transmission line (TL) is formed by a microstrip line. The left‐handed (LH) part of the CRLH‐TL is formed by lumped components. The measured RF‐DC conversion efficiency is 43% at 0.9 GHz and 39% at 2.45 GHz with rectifier size of 0.18λ _o × 0.075λ _o × 0.0002λ _o at 0.9 GHz.     

A Dual‐band and dual‐polarized antenna array for 2G/3G/LTE base stations

A dual‐band antenna array is proposed for the application of base station (BS) in 2G/3G/long term evaluation (LTE) mobile communications. This antenna consists of two independent ±45° dual‐polarized arrays, one of which operates from 1.71 to 2.17 GHz, and the other of which is designed from 2.5 to 2.69 GHz. The proposed BS antenna array has a high isolation of greater than 29 dB and high front‐to‐back ratio of more than 26 dB at the operating frequencies. The measured peak gain is 17.9 and 18.1 dBi for the lower and upper bands, respectively, and the cross polarizations isolation (CPI)(within ±60º of the mainlobe) is 16 dB lower than the broadside co‐polarization. It was confirmed that the proposed antenna array meets the communication standards in China. © 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE 26:154–163, 2016.     

A state‐of‐art review on band‐notch characteristics in UWB antennas

Ultra‐wideband technology has experienced a rapid growth over the last decade for its contribution in different sectors of human society. Printed antennas are considered as preferred platform for implementing this technology because of its alluring characteristics like light weight, low cost, ease of fabrication, integration capability with other systems, etc. Antennas developed for ultra‐wideband applications are desired to have notch characteristics for avoiding interference with other existing radio communication systems. The techniques related to design and developments of printed band‐notched antennas are continuously upgraded for improving the antenna performance. In this article, a comprehensive review has been carried out on ultra‐wideband antennas with band notch characteristics proposed in around last decade. The band notched UWB antennas available in the literature have broadly been classified into five different categories based on their notch characteristics like single band‐notch, dual band‐notch, triple band‐notch, quad/multiple band‐notch, and reconfigurable/tunable band‐notch, respectively. This review exercise may be helpful for beginners working on ultra‐wideband band‐notched antennas and also such a review process is not available in the open literature to the best of author's knowledge.     

Inter‐digital coupled dual‐mode patch resonator with crossed‐island configuration for tri‐band filter design

The miniaturized dual‐mode tri‐band band‐pass filters (BPF) using crossed‐island patch resonator is proposed in this article. The BPF is mainly formed by a square patch resonator in which a crossed‐island configuration is embedded in the patch. The patch size reduction with 74.4% is achieved. By the perturbation and the alternative inter‐digital coupling, the tri‐band responses are obtained. The proposed filter covers the required bandwidths for WLAN band (2.26–3.11 GHz and 5.02–6.0 GHz) and X‐band (7.58–8.41 GHz) applications. Five transmission zeros are placed between three pass‐bands and resulted in a good isolation. © 2013 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:457–463, 2014.     

A novel dual‐band ring coupler based on dual‐band phase inverter

A novel dual‐band ring coupler based on dual‐band phase inverter is proposed. And two types of dual‐band phase inverters (Type I and Type II) are designed in this article. The design method of dual‐band ring coupler is simpler than the traditional ways like replace the single‐band λ/4 transmission line with dual‐band λ/4 transmission line. Its main idea is replacing the wide‐band phase inverter with dual‐band phase inverter. Two dual‐band ring couplers (0.9/2.88 and 0.9/2.43 GHz) using the two types of dual‐band phase inverter, respectively, are simulated and measured. The measured results validate the proposed method.     

Novel offset‐fed dual‐band aperture‐dipole composite antenna: Operating principle and design approach

Operating principle and design approach of a novel dual‐band aperture‐dipole composite antenna are proposed. It is shown that multiple operating modes can be simultaneously excited by employing offset‐feeding technique at first. After the behavior of each mode is studied, the operating principle of the antenna is analyzed and described. Then, an improved dual‐band aperture‐dipole composite antenna is formed and it is designed by using the proposed approach. The antenna is experimentally verified. It is demonstrated that two operating bands for radiation are ranged from 2.36 to 2.58 GHz and from 4.1 to 15.72 GHz, respectively, in which the reflection coefficient are both 相似文献   

Compact meander T‐shaped monopole antenna for dual‐band WLAN applications

A compact coplanar waveguide‐feed monopole antenna with dual‐band characteristics is proposed in this article. The proposed antenna mainly consists of meander T‐shaped monopole and small ground plane embedded with a pair of L‐shaped couple slots and two pairs of I‐shaped notched slots symmetrically. By elongating the meander T‐shaped arms and carefully selecting the positions and lengths of L‐shaped slot and I‐shaped slot, the antenna excites four resonant frequencies at 2.42, 2.52, 4.75, and 5.54 GHz which are formed into two wide bands to cover all the 2.4/5.2/5.8 GHz wireless local area network (WLAN) operating bands, and is with miniaturization structure. Moreover, the antenna can provide nearly dipole‐like radiation patterns and good gains across the dual operating bands. These results prove that the proposed dual‐band antenna is very suitable for WLAN applications. © 2012 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2013.