H-plane Radiation Patterns Research Articles

Fractal dipole antenna for UWB applications

A double-printed elliptical slot inscribed, rectangular fractal dipole antenna for ultrawideband (UWB) applications is presented. The fractal geometry is applied to the dipole elements for size miniaturization and bandwidth enhancement. Further, bandwidth enhancement is achieved using linearly tapered microstrip feed line. The antenna has reflection coefficient less than −10 dB for the frequency range of 3.7–17 GHz. The designed antenna structure has omnidirectional radiation patterns in H-plane and directional in E-plane for UWB band with an average gain of 3 dB. A fidelity factor of 0.60 is achieved between the transmitted and received pulses. A good agreement between the simulated and experimental results is achieved. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:39–47, 2016

Miniaturized Omnidirectional Horizontally Polarized Antenna

A novel miniaturized impedance matched antenna with omnidirectional horizontally polarized radiation pattern is presented. The antenna structure resembles a circular loop formed by a circular array of shunt miniaturized n-fold resonant dipole antennas, which will be referred to as miniature composite wire-loop antenna (MCWLA). The proposed antenna does not require an external matching network and can easily be matched to balanced ports with any desired impedance. MCWLAs can be made to be a very small fraction of the wavelength and yet to provide a relatively high radiation efficiency. The antenna input impedance can be adjusted by the number of array n-folded dipole elements, the number of folds and the diameter of the composite loop. The input impedance can be lowered by increasing the number of elements and/or by decreasing the loop diameter. Conversely, the input impedance, for a fixed number of elements and diameter, can be increased by increasing the fold number. The antenna efficiency increases with increasing the loop diameter. To demonstrate the proposed concept, a MCWLA is designed with diameter ${\lambda}/8$ and is designed and fabricated using the standard PCB approach on a thin substrate ( $\lambda /500$ ). To achieve omnidirectional radiation pattern in H-plane, a minimum of three elements fed in-phase around the inscribing loop are used. It is shown that impedance match to a $50\hbox{-}\Omega$ line can be achieved using fourfold miniaturized dipole elements. The simulation shows strong uniform current distribution on the A transformer balun that is used to connect the balanced port of the antenna to a small coaxial line at the center of the loop. The measured gain, including the loss through the balun, is to be 0 dBi and the gain variation in the H-plane is shown to be less than 0.5 dB for the prototype MCWLA.

A Miniaturized Wide-Beamwidth Circularly Polarized Planar Antenna via Two Pairs of Folded Dipoles in a Square Contour

A circularly polarized (CP) antenna with a wide axial-ratio (AR) beamwidth is presented by placing the two pairs of folded dipoles in a square contour. First, our study demonstrates that the CP radiation can be achieved at the broadside by setting a 90° phase difference between the vertical- and horizontal-paired folded dipole radiators. Second, a radiation pattern subtraction approach is presented to explain how the radiation beamwidth of the paired folded dipoles could be appropriately widened or narrowed according to the radiation pattern subtraction of two opposite electric current densities in the folded dipoles. Using this approach, the E-plane beamwidth of a pair of folded dipoles is made certainly widened, whereas its H-plane counterpart becomes narrowed. On this basis, the E- and H-plane radiation patterns can still be made approximately identical with each other over a wide range of polar angle, even though the distance between dipoles is deliberately shortened. As such, the desired CP antenna with shortened dipole-to-dipole distance and unaffected wide AR beamwidth can be achieved using two pairs of parallel folded dipoles with shortened distance between them instead of linear dipoles in [24] . Finally, a CP printed antenna is designed and fabricated on a single dielectric substrate. Experimental results are found in good agreement with the simulated ones in terms of radiation patterns, gain, AR, efficiency, and reflection coefficient. In particular, the 3-dB AR beamwidth at the central frequency of 1.6 GHz is extended to 135° at $XZ$ -plane and 142° at $YZ$ -plane. Moreover, the overall size of the constituted CP antenna with folded dipoles is decreased to $\mathbf{0}.\mathbf{43}\;{\boldsymbol{\lambda }_\mathbf{0}} \times 0.43\;{\boldsymbol{\lambda }_\mathbf{0}}$ ( ${\mathbf{\lambda }_\mathbf{0}}$ is the wavelength in free space).

Millimeter-wave planar high gain SIW antenna using half elliptic radiation slots

This article reports a high gain millimeter-wave substrate integrated waveguide SIW antenna using low cost printed circuit board technology. The half elliptic slots which can provide small shunt admittance, low cross polarization level and low mutual coupling are etched on the board surface of SIW as radiation slots for large array application. Design procedure for analyzing the characteristics of proposed radiation slot, the beam-forming structure and the array antenna are presented. As examples, an 8 × 8 and a 32 × 32 SIW slot array antennas are designed and verified by experiments. Good agreements between simulation and measured results are achieved, which shows the 8 × 8 SIW slot array antenna has a gain of 20.8 dBi at 42.5 GHz, the maximum sidelobe level of 42.5 GHz E-plane and H-plane radiation patterns are 22.3 dB and 22.1 dB, respectively. The 32 × 32 SIW slot array antenna has a maximum measured gain of 30.05 dBi at 42.5 GHz. At 42.3 GHz, the measured antenna has a gain of 29.6 dBi and a maximum sidelobe level of 19.89 dB and 15.0 dB for the E-plane and H-plane radiation patterns. © 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:709-718, 2015.

두 개의 팔을 가진 초광대역 자기상보형 시뉴어스 안테나

본 논문에서는 Cellular/GSM800, GSM900, ISM, GPS, DCS/GSM1800, PCS/GSM1900, WCDMA/UMTS/IMT2000, WiBro, WLAN, WiMax의 주파수 대역(0.824~5.85 GHz) 전체를 포함하는 초광대역 시뉴어스 안테나를 제안하였다. 제안한 시뉴어스 안테나는 두 개의 팔(arm)로 이루어져 있으며, 자기상보(self-complementary) 구조로 설계하여 주파수 무관 특성을 나타내도록 하였다. 안테나는 클로펜스타인 테이퍼(Klopfenstein taper) 구조의 광대역 발룬(balun)을 사용하여 <TEX>$50{\Omega}$</TEX>에 정합시켰다. 측정 결과, 제안한 안테나의 대역폭은 반사손실 -10 dB를 기준으로 할 때 0.76~6 GHz까지 5.24 GHz로, 목표 주파수 대역을 모두 포함하는 것을 확인하였다. 방사패턴은 E-plane과 H-plane 모두에서 전체 동작 주파수 대역에 걸쳐 거의 변화 없이 양방향성 브로드사이드 빔을 보였으며, 최대 이득은 2.32~6.01 dBi로 측정되었다. This paper presents a ultra-wideband sinuous antenna that operates in a whole frequency range (0.824~5.85 GHz) of Cellular/GSM-800, GSM900, ISM, GPS, DCS/GSM1800, PCS/GSM1900, WCDMA/UMTS/IMT2000, WiBro, WLAN and WiMax. The proposed antenna, which is composed of two sinuous arms, is designed as a self-complementary structure in order to have frequency-independent characteristics. It also uses a wideband balun of Klopfenstein taper structure to match to <TEX>$50{\Omega}$</TEX>. Experimental results show that the -10 dB return loss bandwidth of the proposed antenna is 5.24 GHz that ranges from 0.76 to 6 GHz, which covers all the frequency bands of the various wireless services. Within the entire operating frequency range, the measured radiation patterns in both E-plane and H-plane show nearly constant bidirectional broadside beams and the maximum antenna gain is measured to fall between 2.32~6.01 dBi.

High isolation dual-polarized broadband antenna for base stations

A broadband (1.71–2.17 GHz), high isolation, and dual-polarized suspended plate antenna (SPA) is presented. Modified L-probe feed is used for broadband matching and capacitive coupling. Port isolation between two orthogonally polarized channels is improved by making extensions on suspended plates (SPs) and inserting a vertical ungrounded square tube under the first SP (SP1). The prototyped SPA resulted in 8 ± 0.5 dBi gain and 67° ± 6° symmetric E-plane and H-plane radiation patterns with low cross-polarization levels. Return losses ≤−15 dB and port isolation ≤−30 dB are achieved in the entire band. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:603–607, 2015

Design of Compact Dual-Band/Tri-Band CPW-Fed Monopole Antennas for WLAN/WiMAX Applications

Two compact rupee shaped coplanar waveguide (CPW) fed monopole antennas for WLAN and WiMAX applications are proposed. One of the antennas has a dual band characteristic (measured impedance bandwidth from 2.92---3.7 and 4.6---6.0 GHz) while the other has a triple band characteristic (measured impedance bandwidth from 1.97---2.15, 2.82---3.45 and 4.35---6.0 GHz). Both the proposed antennas measure $$17.5 \times 17.5\times 1.6\,\hbox {mm}^{3}$$17.5×17.5×1.6mm3 in dimensions. The basic radiating element in both the antennas is a rupee shape patch fed by a CPW. The dual frequency band operation is obtained by attaching an additional horizontal L-shape strip. The third frequency band is generated by the introduction of a meander shape strip on one side of the patch. The details of the antenna design along with simulated and experimental results are presented and discussed. The two antennas show nearly omnidirectional radiation patterns in the H-plane and bidirectional radiation patterns in the E-plane with moderate gain in the operating bands. The compact features, simple feeding technique and monopole design make them suitable for portable communication devices.

Radiation Pattern Measurement of a Low-Profile Wearable Antenna Using an Optical Fibre and a Solid Anthropomorphic Phantom

This paper presents a study into radiation pattern measurements of an electrically small dielectric resonator antenna (DRA) operating between 2.4 and 2.5 GHz in the industrial, scientific and medical (ISM) radio band for body-centric wireless communication applications. To eliminate the distortion of the radiation pattern associated with the unwanted radiation from a metallic coaxial cable feeding the antenna we have replaced it with a fibre optic feed and an electro-optical (EO) transducer. The optical signal is then converted back to RF using an Opto-Electric Field Sensor (OEFS) system. To ensure traceable measurements of the radiation pattern performance of the wearable antenna a generic head and torso solid anthropomorphic phantom model has been employed. Furthermore, to illustrate the benefits of the method, numerical simulations of the co-polar and cross-polar H-plane radiation patterns at 2.4, 2.45, and 2.5 GHz are compared with the measured results obtained using: (i) an optical fibre; and (ii) a metallic coaxial cable.

Analysis of Fractal Antenna for Ultra Wideband Application

Aims of this study are to design a simple and compact microstrip-fed Ultra Wide Band (UWB) printed fractal antenna and analyze the performance of the antenna for different iterations. A second iteration of a triangle patch antenna is proposed to perform UWB. Based on the result, the proposed antenna occupies about 6.73 GHz bandwidth covering 3.52-10.24 GHz. The bandwidth is increased about 54.15% for the first iteration of proposed antenna and 69.5% increased for second iteration. A radiation pattern in H-plane and E-plane is also obtained. H-plane of radiation pattern is performed as omni directional and E-plane perfomed like a dipole antenna. Coplanar wave guide is approached to obtain ultra wideband.

Transient response of dual-band-notched ultra-wideband antenna

In the present study, an ultra-wideband (UWB) antenna has been proposed using coplanar waveguide (CPW) feed with dual-band-notch characteristics. Slot-loaded radiator and U-shaped CPW resonator are used for band rejection at 3.5 and 5–6 GHz respectively to reduce interference with existing World interoperability for microwave access and wireless local area network systems. With an extended operating band (measured at 10 dB return loss) the antenna operates successfully over the entire UWB range (3.1–10.6 GHz) with a form factor of 30 × 20 × 1.524 mm3 on a commercially low-cost FR-4 substrate. Experimental measurement results are presented in support of the simulated results for the proposed antenna for practical application. The antenna has been successfully fabricated and measured, showing broadband matched impedance and good omnidirectional radiation pattern throughout the operating bandwidth. Measured time-domain analysis for both the orientations, i.e. face-to-face and side-by-side, yields excellent performance in the open environment scenario. With fairly good and consistent monopole such as omnidirectional radiation patterns in H-plane and linear transmission responses, the proposed antenna is well suited to be integrated within portable devices.

A Corrugated Printed Dipole Antenna With Equal Beamwidths

A corrugated printed dipole antenna with equal beamwidths in the principal planes is proposed, designed, and evaluated. Orthogonal stubs are added to the dipole arms to equalize its radiation patterns. They also reduce the size of the dipole arms. The antenna is designed to operate at 3 GHz, and has dimension of 36 × 80 × 1.58 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> . The -10 dB S 11 bandwidth of the antenna is from 2.75 to 3.62 GHz, i.e., 27.3%. The E- and H-plane radiation patterns of the antenna are nearly equal up to 135 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">°</sup> from the boresight. To confirm the simulation results, the antenna is fabricated and tested, showing good agreement between simulation and measurement results. Its performance as a feed on a deep reflector, with f/D = 0.25 and D = 45 cm is also studied, where f is the focal length of the reflector and D is its diameter. It provides an enhanced bandwidth of 29.6%, equal E- and H-plane radiation patterns of the reflector, and a gain of 21.4 dBi or an efficiency of 69%. The reflector is only 4.5 λ0 in diameter and would suffer significant blockage losses with conventional waveguide feeds. The proposed feed causes negligible blockage, and provides a respectable efficiency. It is a suitable feed for small symmetric reflectors.

Packaging a $W$-Band Integrated Module With an Optimized Flip-Chip Interconnect on an Organic Substrate

This paper, for the first time, presents successful integration of a W-band antenna with an organically flip-chip packaged silicon-germanium (SiGe) low-noise amplifier (LNA). The successful integration requires an optimized flip-chip interconnect. The interconnect performance was optimized by modeling and characterizing the flip-chip transition on a low-loss liquid crystal polymer organic substrate. When the loss of coplanar waveguide (CPW) lines is included, an insertion loss of 0.6 dB per flip-chip-interconnect is measured. If the loss of CPW lines is de-embedded, 0.25 dB of insertion loss is observed. This kind of low-loss flip-chip interconnect is essential for good performance of W-band modules. The module, which we present in this paper, consists of an end-fire Yagi-Uda antenna integrated with an SiGe BiCMOS LNA. The module is 3 mm × 1.9 mm and consumes only 19.2 mW of dc power. We present passive and active E- and H-plane radiation pattern measurements at 87, 90, and 94 GHz. Passive and active antennas both showed a 10-dB bandwidth of 10 GHz. The peak gain of passive and active antennas was 5.2 dBi at 90 GHz and 21.2 dBi at 93 GHz, respectively. The measurements match well with the simulated results.

A Compact Ultra-Wideband Monopole Antenna with Dual Bandstop Characteristics

A compact and simple ultra-wideband microstrip-fed planar antenna with double bandstop characteristic is presented. The antenna consists of a rectangular monopole and two W-shaped slots inserted into the radiating patch and the truncated ground plane. By using a W-shaped slot defected ground structure (DGS) in the feedline, a stopband of 800 MHz (from 5.1 to 5.9 GHz) for band rejection of wireless local area network (WLAN) is achieved. To obtain the other stopband (from 3.7-4.4 GHz), a same shaped slot is etched into the monopole. Moreover, the two stopbands can be controlled by adjusting the length of the slot respectively. The simulation results show that the designed antenna, with a compact size of 38.5 mm×42.5 mm, has an impedance bandwidth of 2.811 GHz for voltage standing wave ratio (VSWR) less than 2, besides two frequency stopbands of 3.74.4 GHz and 5.15.9 GHz. Moreover, the main features including omnidirectional H-plane radiation patterns and the appropriate impedance characteristic are achieved by beveling the radiating patch and the microstrip-fed line of the proposed antenna.

Super High Gain Substrate Integrated Clamped-Mode Printed Log-Periodic Dipole Array Antenna

A compact, low profile, super high antenna gain, and broadband antenna, based on the printed log-periodic dipole array (PLPDA) antenna and the substrate integrated waveguide (SIW) technologies, has been proposed. It is so called substrate integrated waveguide clamped-mode printed log-periodic dipole array (SIW clamped-mode PLPDA) antenna. The arrangement of the dipole elements and feed lines in the SIW clamped-mode PLPDA antenna is designed and optimized. The proposed SIW clamped-mode PLPDA antenna was designed, fabricated, and tested, while a single SIW PLPDA antenna and a 2-element SIW PLPDA array were designed for comparison. The impedance bandwidth and the far-field radiation patterns in both E-plane and H-plane were measured. The measured results show that the performance of the SIW clamped-mode PLPDA antenna is similar to that of the 2-element SIW PLPDA array over the working frequency range 25 GHz-40 GHz, while the proposed antenna has only half the number of dipole elements and feed lines.

E/H 평면 방사 패턴 대칭성 향상을 위해 개구면이 변형된 원형 이중 모드 혼 안테나

본 논문에서는 개구면이 큰 기존 원형 이중 모드 혼의 E/H 평면 방사 패턴 대칭성 향상을 위한 변형된 개구면을 갖는 원형 이중 모드 혼을 제안한다. 제안된 안테나는 급전부, 모드 발생부, 위상정합부로 구성되며, 이 중 위상정합부의 원형 개구면은 E/H 평면의 방사 패턴 대칭성 향상을 위해 타원형 혹은 직사각형으로 변이된 형상을 갖는다. 제안된 안테나와 기존 원형 이중 모드 혼의 성능 비교를 위해 15 GHz에서 동작하는 기존 원형 이중모드 혼과 직사각형 개구면을 갖는 원형 이중 모드 혼을 제작하고 분석하였다. 측정 결과, f/d 비가 1인 반사판 안테나의 최대 개구 효율을 위한 급전 혼의 빔 폭인 -11 dB 빔 폭(<TEX>$53^{\circ}$</TEX>) 내에서 기존 원형 이중 모드 혼의 경우 3.394 dB의 E/H 평면 방사 패턴 차이를 갖는 반면, 제안된 안테나는 오직 0.539 dB 차이를 가진다. In this paper, a circular dual mode horn with modified aperture is proposed to improve a E/H-plane radiation pattern symmetry of a conventional oversized circular dual mode horn. The proposed antenna consists of a feeding section, a mode generation section and a phase matching section which has aperture shape transition from circle to ellipse or rectangle to improve a E/H-plane radiation pattern symmetry. To compare the performances between the proposed antenna and the convenional circular dual mode horn, the conventional circular dual mode horn and the proposed circular dual mode horn with rectangular aperture are fabricated and researched at 15 GHz. The measured results show that the conventional circular dual mode horn has 3.394 dB difference while the proposed antenna has only 0.539 dB difference between E and H-plane radiation patterns within the -11 dB beamwidth(<TEX>$53^{\circ}$</TEX>) which is required beamwidth of the feed horn for the maximum aperture efficiency where f/d ratio of reflector antenna is 1.

An Easily Realizable Band-Notched UWB Antenna

An easily realizable ultrawideband (UWB) monopole antenna, with band-notched characteristics, is presented. The antenna consists of a circular metal radiation patch, fed by a 50-Ω microstrip transmission line and a rectangular ground plane with a notch cut into it. By etching a modified U-shaped slot in the radiating patch and by properly tuning its location and form, band-rejected filtering properties can be achieved easily in WiMAX/WLAN bands. It has good omni-directional radiation patterns in H-plane and a good agreement between simulation and measurement.

Branch Loop Antenna for the Mobile Handset

It`s introduced a BLA(Branch Loop Antenna) that is modified from conventional loop, and verified antenna performances for applying to mobile handset. Branch elements are added to a rectangular loop, and low resonance is obtained by the length of the branch line. When resonance frequency of a single loop is 2.5GHz, BLA had near 900 MHz under the same antenna size. Multiple resonances are established by the locations of branch connection and their lengths. By the implementation and measurement for the dual band BLA, it`s showed 75MHz -10dB bandwidth and -3.03~-1.46dBi average gains with 49.73~71.39% efficiencies at GSM900 band, and 90MHz -6dB bandwidth and -8.14~-2.17dBi average gains with 15.34~60.62% efficiencies at DCS1900 band. And H-plane radiation patterns were omni-directional. These performances are good for the mobile handset antenna.

A Novel Compact UWB Monopole Antenna with Bluetooth and Triple Notch Band

AbstractA novel technique to add an extra Bluetooth band and triple notch bands simultaneously to a compact ultra-wideband (UWB) monopole antenna is presented. This scissors-shaped UWB antenna, covering 2.9 GHz–12.5 GHz, is fed by a special microstrip line. To create an extra Bluetooth band centered at 2.45 GHz, an arc-shaped stub is attached to the high concentrated current area right of the feed line and a rectangular slot is etched in the radiation patch. Besides, a notch band for WLAN (5.6 GHz–6.15 GHz) is also obtained. In addition, by connecting two asymmetric stubs to the feed line, two other notch bands in 3.28 GHz–3.8 GHz for WiMAX and 7.1 GHz–7.76 GHz for downlink of X-band satellite communication systems are achieved. The proposed antenna with compact size of 20 mm × 26 mm is fabricated and measured, showing stable antenna gain and good omni-directional radiation patterns in H-plane.

A Wideband Waveguide Antenna with Nearly Equal E- and H-Plane Radiation Patterns

A novel wideband waveguide antenna with excellent performance is proposed, which is composed of a coaxial-waveguide transition and an open-ended rectangular waveguide loaded with a pair of horizontal umbrella-shaped metallic brims. The brims perpendicular to two broad walls of the waveguide are constructed to modulate the antenna to radiate nearly identical E- and H-plane radiation patterns. A wideband impedance matching performance is achieved with a fractional bandwidth of 40% through the introduction of short-stepped ladders. The antenna has the advantages of simple structure, symmetric radiation pattern, low-cross polarization, moderate back lobe, and almost constant beamwidth.

INVESTIGATION OF CAVITY REFLEX ANTENNA USING CIRCULAR PATCH TYPE FSS SUPERSTRATE

Cavity re∞ex antenna (CRA) employing a circular patch type FSS (Frequency Selective Surface) superstrate is investigated. Analysis in terms of gain, bandwidth (impedance and gain) and radiation pattern has been presented. The aim of this work was to study low proflle CRA having very thin superstrate sizes. In this CRA a circular patch antenna is used as a feeding source. The circular patch type FSS possesses some unique properties favorable for thin superstrate sizes. In practice when the excitation source of the CRA is a probe-fed microstrip antenna with flnite ground plane, substrate and superstrate, cross-polarization increases. In the presented design, the cross polar level has been reduced by choosing the optimum air gap and superstrate geometrical and electrical properties. A CRA with circular patch type FSS ofiers better performance both in terms of gain and impedance bandwidth for, thin superstrates (0:008‚0) while giving a gain of 13dBi and considerably reduced crosspolar level. The proposed antenna exhibit nearly equal E-plane and H-plane radiation pattern. Measurement results are provided to support the simulated results (by Ansoft HFSS). The circular patch type FSS is easy to fabricate and can be embedded into the host proflle.