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1.
    
This article presents the miniaturization of a planar half elliptical ultra‐wideband dipole. By simply placing a concaved arm in close proximity to the original structure, a 45% area reduction in terms of electrical wavelength can be achieved. The proposed antenna exhibits a wide measured return loss bandwidth of 2 to 9.9 GHz and omnidirectional radiation patterns across the band. The design features a footprint size of 41.5 × 41.5 mm2 and an electrical size of 0.28λ × 0.28λ at 2 GHz. Compared with some previously reported planar designs, the proposed antenna presents a more compact electrical dimension and better or comparable bandwidth. Critical geometric parameters of the structure, particularly the concaved arm, are investigated to understand the miniaturization and operating mechanism of the design. Satisfactory correlation between the simulation and measurement data is obtained.  相似文献   

2.
    
A compact size of 40 × 40 mm2 ( λ0 × λ0 ) semi‐elliptical slotted ground structure (SESGS) directional ultra‐wideband (UWB) antenna is proposed for radar imaging applications. A vertical semi‐elliptical slot is inserted into ground and subsequently, an axis of semi‐ellipse is rotated diagonally (with 45°) in direction of the substrate. Axes of semi‐ellipse are optimized symmetrically around the circular patch to work antenna as a reflector. Furthermore, semi‐elliptical slot is rotated horizontally (with 90°) again to improve the impedance bandwidth. Proposed antenna achieves fractional bandwidth around 83% covering the UWB frequency range from 4.40 to 10.60 GHz (S11 < ?10 dB) having 4.5/6/7/8/9.3/10.2 GHz resonant frequencies. Also, antenna is capable to send low‐distortion Gaussian pulses with fidelity factor more than 95% in time‐domain. Measured gain and half power beam width (HPBW) are 6.1‐9.1 dBi and 44°‐29° in 4.40‐10.60 GHz band, respectively, which show an improvement of 1‐3 dBi in gain and half power beam‐width is reduced by 5°‐10° when compared with previously designed antennas. Experimental results show good agreement with CST simulation.  相似文献   

3.
    
In this article, a wideband circularly polarized (CP) dielectric resonator (DR) over an asymmetric‐slot radiator based hybrid‐DR antenna is proposed with bi‐directional radiation characteristics. Bi‐directional CP radiation of the dual sense is obtained using a rectangular‐DR over asymmetric‐rectangular‐slot radiator with L‐shaped feed line. The asymmetric‐slot radiator feed by L‐shaped stub with the coplanar waveguide is used for generating two orthogonal modes, namely TE x δ11 and TEy1δ1 in the combined (rectangular‐DR and asymmetric‐slot radiator) hybrid‐DR antenna, which is verified by the distribution of electric field inside the rectangular DRA. The measured reflection coefficient bandwidth (S11 < ?10 dB) and axial ratio (AR) bandwidth (AR < 3 dB) of the hybrid‐DR antenna are 80.5% (1.87‐4.39 GHz) and 43.8% (1.75‐2.73 GHz), respectively. The antenna radiation is in the broadside (θ = 0°, ? = 0°) direction as well as in the backside (θ = 180°, φ = 0°) direction with equal magnitudes in both the directions. Right‐handed and left‐handed CP waves are achieved respectively, in the boresight (+Z) and the backside (?Z) directions. The proposed CP hybrid‐DR antenna gives an average gain of 3.55 dBic and radiation efficiency of 95.0% in both directions. The proposed antenna covers various wireless useful bands such as ISM 2400 band, Wi‐Fi, Bluetooth, and Wi‐MAX (2.5‐2.7 GHz).  相似文献   

4.
    
Investigation results are presented for a cylindrical dielectric resonator antenna (DRA) with a central airgap, which is excited using a coaxial probe connected to a wire monopole. By selecting the proper values of airgap and monopole heights, a desired impedance bandwidth (S11 ≤ ?10 dB) from 40% to 67% can be achieved. The proposed DRA provides monopole like omni‐directional radiation patterns with low crosspolarization levels throughout the bandwidth. Prototype DRA was fabricated with equal heights of the airgap and monopole and experimentally verified for both the impedance matching and radiation performance. Simulated and measured bandwidths of 67% and 64%, respectively, were obtained with acceptable peak realized gain. The simulated and measured radiation patterns agree well. Furthermore, this DRA is investigated for beam focusing properties when implemented in a circular array consisting of four‐elements on a circular finite ground plane. © 2013 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:92–101, 2014.  相似文献   

5.
    
A dielectric resonator combining two cylindrical dielectrics of different material and height and excited by a coaxial probe is considered. The effect of the antenna parameters, such as the ratio of the height and radius of the dielectrics and the effect of the probe length, are investigated. Analysis of the antenna is performed numerically using the method of moments (MoM) and verified by the finite-difference time-domain (FDTD) method. Agreement between the two methods is excellent. The performance of the antenna on a cellular-communication system is also considered. © 2004 Wiley Periodicals, Inc. Int J RF and Microwave CAE 14, 441–446, 2004.  相似文献   

6.
    
A wideband omnidirectional filtering patch antenna with high selectivity is proposed in this article. The annular ring is surrounded by the hexagonal patch with inner circle, whereas a series of shorting vias are regularly distributed among them and a copper top hat is suspended right on the top of the radiator, respectively. And, omnidirectional pattern is mainly performed on account of the symmetry and center‐fed structure. In addition, broadband performance is achieved by merging three resonant modes, which include the TM01 and TM02 modes of the annular ring and the TM02 mode of the hexagonal patch with inner circle. Taking advantages of the hexagonal patch and six shorting vias in it, two radiation nulls are provided in the upper band. Besides, another radiation null is generated in the lower band by reason of the top hat and other shorting vias. As a result, an ideal quasi‐elliptic bandpass response, high selectivity, and good out‐of‐band rejection are obtained simultaneously. The proposed filtering patch antenna, with a profile of 0.056 λ 0, shows a wide impedance bandwidth of 30.2% from 2.05 to 2.78 GHz. The average gain in the passband is about 6.5 dBi, and the out‐of‐band suppression level is greater than 15 dB in the wide stopband.  相似文献   

7.
    
In this article, an electrically coupled dual semicylindrical dielectric resonator antenna (SC‐DRA) is presented and discussed for wideband applications. The two SC‐DRAs are placed in an inverted arrangement and fed by a coaxial probe to excite the fundamental mode TM 11δ and higher order mode TM 21δ. In the proposed design, wideband performance is obtained by combining the fundamental and higher order mode. Proposed wideband antenna is showing simulated and measured input impedance bandwidth (|S11| ≤ ?10 dB) of 57.94% (3.8‐6.9 GHz) and 64.4% (3.38‐6.6 GHz), respectively. The far field radiation patterns are found to be consistent and 3‐dB beamwidth of 49° and 30° has been achieved at 4.11 and 6.48 GHz, respectively within the working band. This design attains an average gain of 5.65 dBi and radiation efficiency of 97%, respectively.  相似文献   

8.
    
This article concentrates on the design and analysis of a novel Minkowski fractal‐based antenna design with the aid of triangular dielectric resonator (TDR) elements for wideband wireless applications. mode is excited inside equilateral TDR antenna with the help of coaxial probe feed. Wide impedance bandwidth has been achieved by reducing the quality factor with the help of increasing surface area‐to‐volume ratio of radiating structure. Another important feature of this article is that recurrence formulas are derived to calculate the fraction of surface area to volume of proposed fractal antenna up to nth iteration. The proposed antenna design is fabricated and measured up to third iteration to verify its simulated outcomes. Practically measured outcome confirms that the proposed antenna design operates over the frequency range, that is, 2.23‐3.1 GHz with the maximum gain of 3.62 dBi. These features make it appropriate for wireless LAN (2.4 GHz) and WiMAX (2.5 GHz) applications.  相似文献   

9.
    
A tunable band‐notch printed monopole antenna is presented, exhibiting a wide impedance bandwidth from 1.5 to 5.5 GHz with good impedance matching (VSWR ≤ 2) and a tunable rejected frequency band from 2.38 to 3.87 GHz. The band‐notching is achieved by adding an inner chorded crescent element within a driven element of a similar shape. By varying the value of the varactor, which is placed between the inner and outer arcs, the desired variable rejected can be obtained. Simulated and measured results show wide impedance bandwidth with a tunable band notch, stable radiation patterns, and consistent nearly constant gain. The antenna is suitable for mobile and portable applications. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:403–412, 2015.  相似文献   

10.
    
In this article, the design and analysis of a double‐ridged conical horn antenna with high gain and low cross polarization for wideband applications is presented. Double‐ridged pyramidal horn antennas have been investigated in many references. There are no papers in the literature which are devoted to design and analysis of double‐ridged conical horn antenna. The designed antenna has a voltage standing wave ratio (VSWR) less than 2.1 for the frequency range of 8–18 GHz. Moreover, the proposed antenna exhibits extremely low cross polarization, low side lobe level, high gain, and stable far‐field radiation characteristics in the entire operating bandwidth. A new technique for synthesizing of the horn flare section is introduced. A coaxial line to circular double‐ridged waveguide transition is introduced for coaxial feeding of the designed antenna. The proposed antenna is simulated with commercially available packages such as CST microwave studio and Ansoft HFSS in the operating frequency range. Simulation results for the VSWR, radiation patterns, and gain of the designed antenna over the frequency band 8–18 GHz are presented and discussed. © 2008 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2009.  相似文献   

11.
    
In this article, a novel approach is introduced for the design of wideband antennas in a specified frequency bandwidth (BW). In the proposed approach, the frequency BW is divided into some sub‐bands. Then, the narrowband antennas are designed for the consecutive frequency sub‐bands, and the antennas are connected together by a proposed active circuit, so that their frequency BWs combined. The proposed active circuit may be used to connect as many as antenna needed for the design. An active microstrip antenna is designed for the frequency BW of 4–10 GHz with a gain better than 5 dB by the proposed method. Fabrication and measurement results show the effectiveness of the proposed methodology. © 2010 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2010.  相似文献   

12.
    
An H‐shaped dielectric resonator array antenna is presented for wideband applications. The proposed antenna is excited by slot feed mechanism and investigated experimentally. The antenna covers the frequency ranges from 1.41 to 2.59 GHz, and 4.73 to 6.06 GHz with the corresponding impedance bandwidth of 59% and 24.65%, respectively. The simulation results fulfill the bandwidth requirements of IEEE 802.11a/b/g (2.4‐2.484 GHz/5.15‐5.35 GHz/5.725‐5.825 GHz) for Wireless local area network (WLAN) applications. The proposed antenna has simple structure, easy to fabricate and its measured radiation pattern shows a reliable performance in the desired operating bands.  相似文献   

13.
    
A compact wideband planar monopole antenna is designed and optimized based on artificial neural network (ANN) models. The antenna is suitable for DCS, PCS, DECT, PHS, IMT‐2000, UMTS, and WLAN in mobile communication. The design time decreases dramatically due to using the ANN models. © 2003 Wiley Periodicals, Inc. Int J RF and Microwave CAE 13: 316–320, 2003.  相似文献   

14.
    
Two wideband tapered slot antennas are designed, fabricated, and tested. The first antenna, which is fabricated on a high dielectric constant substrate (?r = 10.2), shows a measured return loss of better than 10 dB from 1.6 to 12.4 GHz (7.7:1 bandwidth), and an antenna gain varying from 3.6 to 7.8 dBi. The second antenna is built on a low dielectric constant substrate (?r = 2.2), and demonstrates return loss of better than 10 dB from 1.8 to 15.2 GHz (8.4:1 bandwidth). The second antenna also has improved antenna gain, from 5 to 15.6 dBi, and is used to build a wideband 1 × 4 H‐plane phased array with a total gain of 9–17 dBi and a beam steering angle of ±15° from 3 to 12 GHz. © 2007 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2007.  相似文献   

15.
    
In this article, a new wideband circularly polarized (CP) antenna is presented. The antenna is composed of a circular‐loop feeding structure which provides sequential phase (SP), four primary‐parasitic crown patches and four secondary‐parasitic crown patches. The circular‐loop SP structure is used to feed the two pairs of crown patches by a capacitively coupled way. The presented antenna features a wide 10‐dB impedance bandwidth (IBW) of 23% (6 GHz, 5.31‐6.69 GHz), and a wide 3‐dB axial ratio bandwidth (ARBW) of 11.1% (5.875 GHz, 5.55‐6.2 GHz). The proposed antenna features compact structure and broad 3 dB‐ARBW, which could include the WLAN (5.725‐5.85 GHz), ITS (5.8 GHz), and WIFI (5.85‐5.925 GHz) band.  相似文献   

16.
    
In this article, a novel inverted L‐shaped microstrip‐fed wideband circularly polarized (CP) modified square‐slot antenna is designed. By cutting a pair of triangle chamfers and introducing a pair of triangle patches at the square‐slot, the antenna achieves a wideband CP radiation. Moreover, CP performance of the antenna can also be remarkably enhanced by protruding an L‐shaped strip and embedding a tuning rectangle slot into the slot ground. The measured results demonstrate that the axial‐ratio bandwidth for AR < 3 is 75.1% (from 4.45 to 9.8 GHz) and the impedance bandwidth (|S11| < ?10 dB) reaches 65.8% (from 4.95 to 9.8 GHz). In addition, surface current studies are performed to illustrate the operating mechanism of CP operation, and the antenna has bidirectional radiation characteristics with an average gain of ~4 dBic within the CP band.  相似文献   

17.
    
A wideband circularly polarized (CP) dielectric resonator antenna (DRA) loaded with the partially reflective surface for gain enhancement is presented in this article. First, the DRA is excited by a microstrip line through modified stepped ring cross‐slot to generate the circular polarization. Four modified parasitic metallic plates are sequentially placed around the DRA for greatly widening the axial‐ratio bandwidth. Then, a partially reflective surface is introduced for enhancing the gain performance and further improving the CP bandwidth as well. Finally, an optimized prototype is fabricated to verify the design concept. The measured results show that the proposed DRA achieves 54.3% impedance bandwidth (VSWR<2) and 54.9% 3‐dB AR bandwidth. Besides, its average and peak gains are 10.7 dBic and 14.2 dBic, respectively. Wide CP band and high gains make the proposed DRA especially attractive for some broadband wireless applications such as satellite communication and remote sensing.  相似文献   

18.
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19.
    
In this article, a new broadband circularly polarized (CP) microstrip patch antenna (MPA) with a sequential phase (SP) square‐loop feeding structure is proposed. The presented antenna is composed of a square‐loop feeding structure, four L‐shaped parasitic patches with L‐shaped slots, four parasitic square patches, and a corner‐truncated square patch. At first, a SP square‐loop is designed as a feeding structure. Then, four L‐shaped parasitic patches with L‐shaped slots are utilized to generate one CP mode by a capacitive coupled way. At last, four parasitic square patches and a corner‐truncated square patch are together placed above the SP feeding structure to broaden the circularly polarized bandwidth (CPBW). The presented antenna has a wide 3‐dB axial ratio bandwidth (ARBW) of 16.7% (5.4 GHz, 4.95‐5.85 GHz), and a wide 10‐dB return loss bandwidth of 25.5% (5.5 GHz, 4.8‐6.2 GHz). The proposed antenna features compact structure and broad 3‐AR bandwidth which could completely cover the WLAN (5.725‐5.85GHz) band. Therefore, the proposed antenna is suitable for circular polarization applications in C band.  相似文献   

20.
    
In this article, a hybrid microstrip fed dual‐cylindrical dielectric resonator antenna (dual‐CDRA) has been proposed for the sub‐6 GHz band application with a wide circular polarization band. The proposed hybrid microstrip feed cylindrical dielectric resonator antenna utilizes an S‐shaped microstrip feed line to excite fundamental HE11δ like mode and hybrid mode in dual‐CDRAs. The presented antenna structures are acting as monopole antenna separately with 48.75% (3.88‐6.38 GHz) bandwidth whereas both radiators called dual‐CDRAs enhances the bandwidth up to 93.06% (2.16‐5.92 GHz) in addition with an axial ratio bandwidth of 15.2% (3.52‐4.1 GHz). The proposed antenna is applicable for WiMAX (3.4‐3.69 GHz), and WLAN application of 802.11d and 8.02.11e IEEE standard. For validation of simulated results, an antenna prototype has been fabricated and experimentally verified. A good agreement between simulation and measured results are obtained. The simulation results have been carried out by using Ansys HFSS 14.0 version software.  相似文献   

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