Zeroth-order Resonance Mode Research Articles

Dual Zeroth-Order Resonant USB Dongle Antennas for 4G MIMO Wireless Communications

A multiband multiple-input multiple-output (MIMO) antenna system consisting of two antenna elements has been proposed for 4G USB dongle application. The designed MIMO antenna system with a compact volume of 25 mm × 30 mm × 3.5 mm operates in two zeroth-order resonance (ZOR) modes to cover the LTE band 13 (746–787 MHz), GSM850/900 (824–960 MHz), and LTE band 7 (2500–2690 MHz) simultaneously. A pair of L-shaped parasitic strips and an etching slot on the ground are employed to achieve good isolation between two elements. Measurement results show that proposed MIMO antenna system has total efficiency over 40% across the operation band and isolation less than −8 dB at the lower band and −16 dB at the upper band, respectively.

Zeroth‐order resonant circular patch antenna based on periodic structures

The circular patch antenna loaded with a periodic structure implementing a composite right/left-handed transmission line (TL) is introduced. The corresponding circuit model of the radial TL is derived to analyse this circular antenna. Since the unit cells of this TL can support arbitrary phase shift, the antenna can form negative modes, positive modes and zeroth-order resonant (ZOR) modes. For a ZOR antenna, the resonant frequency is independent of its physical size. The resonant frequency, input impedance and radiation characteristics of the ZOR circular antenna are analysed in terms of the physical parameters of the unit cells. Two ZOR circular antennas are designed showing monopolar radiation patterns. One is electrically extremely large, yielding a high directivity, and the other one is electrically small.

Bandwidth enhancement metamaterial antenna based on transmission line approach

ABSTRACTA composite right‐/left‐handed transmission line metamaterial antenna with enhanced bandwidth and efficiency is proposed. The antenna combines zeroth‐order resonant (ZOR) and positive‐order resonant (POR) modes for the bandwidth enhancement. An asymmetrical coplanar waveguide technique is used to feed the antenna and also to achieve certain degree of compactness. The overall size of the antenna is 0.32λ0 × 0.38λ0 × 0.012λ0 (40 × 48 × 1.52 mm) at 2.4 GHz. Simulation results show that a bandwidth enhancement of 41% is obtained with the radiation efficiencies of 95 and 97% for the ZOR and POR modes, respectively. The measured impedance bandwidth shows that the antenna has potential applications for WLAN (2.39–2.45 GHz) and WiMAX (2.5–2.69 GHz) operations. The simulated and measured antenna performances in terms of return loss and the radiation patterns are presented and compared. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:252–256, 2015

Dual mode metamaterial antenna for wideband applications

A dual mode metamaterial antenna is proposed. The antenna is a monopole loaded with metamaterial (MTM) unit cell. An asymmetrical coplanar waveguide (ACPW) technique is employed to achieve a certain degree of compactness. The overall size of the antenna is 0.32λ0 × 0.21λ0 (39 × 25 mm2) at 2.5 GHz. The bandwidth enhancement is achieved when zeroth-order resonance (ZOR) mode is merged to the positive order resonance (POR) mode. Simulated results show that a bandwidth enhancement of 39% is obtained with the radiation efficiencies of 75% and 91% for the ZOR and POR modes, respectively. The return loss response shows that the designed antenna is matched and able to work well within a frequency range of 2.4567–3.6008 GHz, which is suitable for WiMAX applications (2.5–2.69 GHz/3.3–3.365 GHz). The simulated and measured antenna performances in terms of return loss and the radiation patterns are presented and compared. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1846–1850, 2014

A NOVEL SINGLE FEED OMNIDIRECTIONAL CIRCULARLY POLARIZED ANTENNA WITH WIDE AR BANDWIDTH

A novel omnidirectional circularly polarized (CP) antenna with single feed is proposed for 2.4GHz WLAN applications. Based on the zeroth-order resonance (ZOR) mode of epsilon negative (ENG) transmission line (TL), the antenna excites uniform vertically polarized E-fleld just as the monopole does. A modifled Alford loop with electromagnetic coupling fed by L-shaped strip consists of four curved branches, which is placed on the top of the antenna and generates an equivalent horizontally polarized magnetic dipole mode. Once the two orthogonally polarized components are equal in amplitude but difierent in phase by 90 - , omnidirectional CP wave can be obtained. The measured results show that the impedance bandwidth (S11 < i10dB) is 6% (2.38{2.53GHz), and the 3-dB axial ratio bandwidth in the azimuth plane is very wide which achieves 54% (1.60{2.80GHz). Additionally, the 3-dB axial ratio beamwidth is over 50 - for radiation pattern in elevation plane. Moreover, the antenna achieves excellent omnidirectional right-hand CP performance with a variation of 0.5dB in the azimuth plane and an average gain over 1.5dB across the operating band, which are well applied to the wireless system.

Compact Differential Dual-Frequency Antenna Based on Metamaterial

In this paper, a compact differential dual-frequency antenna based on metamaterial is presented. To realize the dual-frequency operation of the left-handed and zeroth-order resonant modes, a ring slot and two diagonal slots are embedded in the radiating patch, and via holes are employed to connect the patch and the ground plane. In order to improve the impedance matching of the antenna, four corners are truncated in the ground plane. The proposed antenna has a compact size of 40 mm × 40 mm, which equals to 0.25 λ1 × 0.25 λ1 (λ1, the guided wavelength at f1). The simulated results show that the proposed antenna can operate at 0.89 and 1.79 GHz bands. Meanwhile, good radiation performances are achieved.

Hybrid Zeroth-Order Resonance Patch Antenna With Broad $E$-Plane Beamwidth

In this paper, a hybrid zeroth-order resonance (ZOR) patch antenna with a broad <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">E</i> -plane beamwidth is presented. In order to obtain the broad beamwidth of an antenna, a TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">010</sub> (λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> /2) mode and a ZOR mode are combined. By dividing the incident power to two modes, the <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">E</i> -plane beamwidth of a TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">010</sub> mode can simply be controlled. To generate the TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">010</sub> mode and the ZOR mode, simultaneously, the mushroom antenna is inserted in a rectangular patch antenna with an etched rectangular hole and a single feed is employed between two radiators. The incident power to each antenna can be controlled by using the gap of a feed. Thus, the optimum incident power ratio having the broadest <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">E</i> -plane half power beamwidth (HPBW) is obtained. As a result, the <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">E</i> -plane HPBW of the proposed antenna is measured as 115° and broadened by 53%, compared with that of the conventional rectangular patch antenna. Moreover, the bandwidth and the efficiency of the antenna are measured to be 3.3% and 92%, respectively. Finally, the measured results show good agreements with the simulated ones.

A NOVEL BROADBAND ASYMMETRIC COPLANAR WAVEGUIDE (ACPW)-FED ZEROTH-ORDER RESONATOR ANTENNA BASED ON EPSILON NEGATIVE TRANSMISSION LINE

A broadband zeroth-order resonant (ZOR) antenna based on asymmetric coplanar waveguide (ACPW) is presented. By adopting the epsilon negative transmission line (ENG-TL), a zeroth-order resonance mode can be achieved. We employ an asymmetric coplanar waveguide structure which ofiers the design freedom to realize the broadband ZOR antenna, where the antenna's bandwidth is characterized by the equivalent circuit parameters. The antenna has the compact unit cell dimensions of 5 £ 13:8mm 2 . The measured results show that the operating bandwidth is about 1050MHz (1.90{ 2.95GHz), and the peak gain and radiation e-ciency are 2.46dBi and 91% at zeroth-order 2.3GHz. Owing to the characteristics of broad bandwidth, high e-ciency, omnidirectional radiation, and easy manufacturing, the proposed ACPW ZOR antenna is very suitable for modern wireless communication systems (UMTS, WLAN, WIMAX, LTE).

Wideband folded mushroom zeroth‐order resonance antenna

In this study, a wideband folded mushroom zeroth-order resonance (ZOR) antenna is presented. To obtain a wide bandwidth, the frequency of the TM010 (λ0/2) mode is down-shifted to the frequency of the ZOR mode by folding a mushroom structure without any additional structure. Thus, the folded mushroom antenna operates over two modes, resulting in a wide bandwidth. The antenna has a dimension of 0.365λ0 × 0.247λ0 × 0.182λ0 at the centre frequency. Its 10 dB fractional bandwidth is measured as 68.3%. The maximum gains of 3.32 and 3.41 dBi are measured at the ZOR mode and the TM010 mode, respectively. Finally, the measured results show good agreements with the simulated results.

MULTIFREQUENCY MONOPOLE ANTENNAS BY LOADING METAMATERIAL TRANSMISSION LINES WITH DUAL-SHUNT BRANCH CIRCUIT

The theory and design of a new family of multifrequency monopole antennas by smartly loading a set of complementary metamaterial transmission line (CMTL) unit cells are investigated. The distributed CMTL elements, epsilon negative (ENG) or double negative (DNG) through incorporating additional capacitive gaps, contain a Koch-shaped extended complementary single split ring resonator pair (K-ECSSRRP) etched on the signal strip. The K- ECSSRRP features dual-shunt branches in the equivalent circuit model, rendering a distinguished resonator with dual zeroth-order resonant (ZOR) modes. By smartly controlling the element layout and loading difierent numbers of unit cells, ten antennas covering difierent communication standards (GSM1800, UMTS, Bluetooth, DMB and WIMAX) are designed and four of them are fabricated and measured. At most of operating frequencies, the antennas exhibit impedance matching better than i10dB and normal monopolar radiation patterns. Numerical and experimental results both conflrm that the single-cell or dual-cell ENG and DNG CMTL-loaded monopoles exhibit almost identical dual ZOR modes. Moreover, the loaded elements also contribute to the radiation, which is the major advantage of this

A Novel Compact Multiband Antenna Employing Dual-Band CRLH-TL for Smart Mobile Phone Application

In this letter, a novel dual zeroth-order resonance (ZOR) by using composite right- and left-handed (CRLH) metamaterial transmission lines structure is proposed for compact multiband antenna design of a smart mobile phone. The theory of ZOR and multimode technique are particularly recommended to design a compact multimode antenna covering GSM850/900 (824-960 MHz) and DCS1800/PCS1900/UTMS (1710-2170 MHz). In order to achieve a broad operation bandwidth, the proposed antenna consists of three parts that can generate two ZOR modes covering the lower band and λ/4 resonant mode covering the upper band. The simulated and measured results show that it has the performance of good radiation pattern and high efficiency, which can meet the requirement of the smart handset. The effect of each part of the proposed antenna on the performance is also analyzed, which is in agreement with the ZOR theory. In addition, the proposed antenna is also applicable to other wireless communication terminals.

접힌 기생 패치를 이용한 확장된 대역폭을 갖는 하이브리드 메타 물질 안테나

본 논문에서는 접힌 기생 패치를 이용하여 확장된 대역폭을 갖는 하이브리드형 메타 물질 안테나를 제안한다. 안테나의 대역폭을 확장하기 위해서 버섯 구조 안테나의 영차 공진 모드와 일반적인 패치 안테나의 기본모드인 <TEX>$TM_{010}$</TEX> 모드를 이용하였다. 일반적인 패치 안테나 내부에 사각 형태의 홀을 에칭하고, 외부에 접힌 기생패치를 추가함으로써 안테나의 크기 변화 없이 <TEX>$TM_{010}$</TEX> 모드의 공진 주파수를 영차 공진 모드의 공진 주파수 쪽으로 근접시킬 수 있다. 따라서 제안된 안테나는 영차 공진 모드부터 <TEX>$TM_{010}$</TEX> 모드까지 동작하는 넓은 대역폭을 가지게 된다. 결과적으로 측정된 안테나의 비대역폭은 12 %이고, 동작 주파수 대역에서 75 % 이상의 방사 효율을 갖는 것으로 확인되었다. In this paper, using a folded parasitic patch, a hybrid metamaterial antenna having the enhanced bandwidth is presented. To obtain a broad bandwidth of the antenna, a zeroth-order resonance(ZOR) mode of a mushroom antenna and a <TEX>$TM_{010}$</TEX> mode of a conventional patch antenna are combined. By employing an etched rectangular hole and a folded parasitic patch in the conventional patch antenna, a resonance frequency of the <TEX>$TM_{010}$</TEX> mode can be down-shifted toward that of the ZOR mode without changing the size of the antenna. Therefore, the proposed antenna has broad bandwidth which ranges from the ZOR mode to the <TEX>$TM_{010}$</TEX> mode. As a result, a fractional bandwidth of the proposed antenna is measured as 12 % and a radiation efficiency is above 75 % in whole band.

무선 전력 전송용 High-Q 스파이럴 영차 공진기

In this paper, various spiral zeroth-order resonators are proposed for wireless power transmission. Since a zerothorder resonance(ZOR) mode of meta-material transmission lines has the characteristic of an infinite wavelength, its frequency is independent of physical length. Also, to obtain high transmission efficiencies high-Q resonators and strong coupling coefficient between coupled resonators are required. Therefore, the resonators consist of spiral inductor and lumped capacitor to use the ZOR mode and they are optimized via parametric study and circuit analysis for a high-Q resonator design. The optimized resonators are simulated and compared with a conventional spiral resonator and one of them was fabricated and measured. The fabricated one has a dimension of () and the transmission efficiency of 80 % is measured at 13.56 MHz at transmitted distance of 40 cm.

Dual-Band Omnidirectional Circularly Polarized Antenna Using Zeroth- and First-Order Modes

This letter discusses the development of a dual-band omnidirectional circularly polarized (CP) antenna using the zeroth- and the first-order resonance modes of epsilon-negative (ENG) transmission lines (TLs). The antenna is based on a circular mushroom structure with curved branches and designed without additional feeding parts for a 90 ° phase difference between two orthogonal modes as well as additional radiators for dual-band operations. A left-hand CP (LHCP) and a right-hand CP (RHCP) are obtained at the zeroth- and the first-order resonance modes, respectively, because the current direction of the curved branch, which is related to a horizontal polarization, at the zeroth-order resonance (ZOR) mode is opposite to that at the first-order resonance (FOR) mode. The measured average axial ratios at the resonance modes in the azimuthal plane are 1.57 and 0.86 dB, respectively. The measured average LHCP and RHCP gains are - 0.24 dBic at the ZOR mode and -0.51 dBic at the FOR mode, respectively. These results are congruent with simulated data.

CRLH ZOR ANTENNA OF A CIRCULAR MICROSTRIP PATCH CAPACITIVELY COUPLED TO A CIRCULAR SHORTED RING

In this paper, a novel Metamaterial (MTM) CRLH Zeroth Order Resonance (ZOR) Circular microstrip patch antenna is proposed to have a monopole antenna pattern due to the completely closed loop of a magnetic current around the structure, and reduced proflle and size due to the left-handedness. Difierent from other ZOR antennas of 1D periodic arrays with shorted patches, we suggest 1 circular patch capacitively coupled to 1 circular shorted ring to have ZOR and i1st resonance modes. The antenna is designed and modeled with equivalent circuits for the coaxial-fed central patch and the circular shorted ring and verifled by the comparison with 3D EM simulation of the physical structure. The no-phase variation at the ZOR (2.4GHz) and the i1st resonance mode (2GHz) as the metamaterial properties are proven with electric fleld distributions and far-fleld patterns. The measurement shows there exist the ZOR and the i1 resonance modes despite the frequency shift from the simulation, which is proven by the monopolar radiation pattern and broadside radiation pattern, respectively. So the advantages of the proposed antenna will be addressed with the low-proflle monopole at the ZOR and the size reduction efiect at the i1st resonance.

Omnidirectional Circularly Polarized Antenna Utilizing Zeroth-Order Resonance of Epsilon Negative Transmission Line

The omnidirectional circularly polarized (CP) antenna using a circular mushroom structure with curved branches is proposed. The antenna is based on the zeroth-order resonance (ZOR) mode of epsilon negative (ENG) transmission line (TL) to obtain a vertical polarization and an omnidirectional radiation pattern. Also, the horizontal polarization is obtained by the curved branches. The 90° phase difference between two orthogonal polarizations is inherently provided by the zeroth-order resonator. Therefore, the antenna has an omnidirectional CP radiation pattern in the azimuthal plane. In addition, this antenna is planar type and simply designed without a dual feeding structure and 90° phase shifter. The measured average axial ratio and left-hand (LH) CP gain are 2.03 dB and - 0.40 dBic, respectively, in the azimuthal plane.

A Circularly Polarized Array Composed of Linear Polarized Microstrip Patches Fed by Metamaterial Transmission Line

A novel single-feed circularly polarized antenna array is constructed by a 2 × 2 array of four square linear polarized microstrip patches with orthogonal orientation and phase shift of 90° in between. The sequential rotation and suitable phasing of linear polarized microstrip patches improve the radiation pattern symmetry and input impedance matching of the array antenna. A metamaterial transmission line is designed and applied to feeding the antenna array. The metamaterial transmission line works at its zeroth order resonant mode and there is no phase shift between its four output ports. A circularly polarized antenna array at 5.8 GHz is built and demonstrated, which is fed by the metamaterial transmission line. The antenna array is compact and the whole dimension is about 1.1λ g 2. The antenna gain reaches 9 dBi, and shows a good axial ratio. Experimental results and simulation agree well.

A BROADBAND PIFA WITH ZEROTH-ORDER RESONATOR LOADING

A printed broadband planar inverted-F antenna (PIFA) with zeroth-order resonator (ZOR) loaded is proposed, whose shorting strip of the PIFA is replaced by an interdigital capacitor and thin inductive strip in series. The loaded interdigital capacitor and thin inductive strip act as a shorting strip at the 3.1 GHz, which allows the antenna to maintain its regular performance. Around 2.0 GHz, the antenna with the interdigital capacitor and thin inductive strip works on the zeroth-order resonance mode, which makes the physical size be independent of the wavelength. By merging the two modes, a broadband performance can be achieved. The size of the antenna is only 12.5mm× 7.81mm× 1.6mm with single layer. The measured antenna bandwidth is 1.63 GHz (about 65%), total gain is above 2.5 dBi and the simulated radiation efficiency is over 90% in the working band. Especially the antenna has same direction of the radiation patterns in the broadband. In the end, the antenna with lumped elements loading is also discussed.

Offset-fed metamaterial antenna for radiation mode generation with efficiency improvement

In this paper, a new offset-fed metamaterial antenna based on a slot-loaded composite right/left-handed transmission line is proposed. Two antennas, namely a centre-fed metamaterial antenna and an offset-fed one, have been investigated. The offset-fed metamaterial antenna generates additional resonant modes with endfire radiation like a patch antenna, whereas the centre-fed one produces only broadside radiation like a monopole antenna. The one-dimensional equivalent circuit model is applied to analyse the slot-loaded structure and the two-dimensional microstrip cavity model is employed for the offset-fed structure. The measured results are in good agreement with the theoretical analysis, especially in radiation pattern and radiation efficiency. The radiation efficiency is pronouncedly enhanced up to 27.6% at the zeroth-order resonant mode and to 56.8% at the additionally generated mode (quasi-TM010) because of the slot effect on the ground plane.

영차 공진을 이용한 전방향성 원형 편파 안테나

In this paper, the omnidirectional circularly polarized(CP) antenna using arc-shaped mushroom structure with curved branch is proposed. To obtain a vertical polarization and an omnidirectional radiation pattern, the CP antenna uses zeroth-order resonance(ZOR) mode of composite right and left handed(CRLH) transmission line. The horizontal polarization is achieved by the curved branches. Also, the spacing between curved branch and arc-shaped mushroom structure gives the phase difference between vortical and horizontal polarization. The proposed antenna, therefore, has an omnidirectional CP radiation pattern In the azimuthal plane. The electrical size of the proposed antenna is reduced by 38%, compared with that of the previously presented omnidirectional CP antenna. In addition, the CP antenna is simply designed without phase shifter and dual feed line. The proposed antenna uses a Bazooka balun for good impedance matching and radiation pattern. To improve 3 dB axial ratio in XY plane, the designed antenna is optimized. After optimization, the measured 3 dB axial ratio in XY plane is observed in .