Artificial Magnetic Conductor Ground Plane Research Articles

Omnidirectional Circularly Polarized Monopole Antennas on Artificial Magnetic Conductor Ground Plane

Omnidirectional Circularly Polarized Monopole Antennas on Artificial Magnetic Conductor Ground Plane

Plasma-Based Artificial Magnetic Conductor for Polarization Reconfigurable Dielectric Resonator Antenna

Polarization reconfigurable dielectric resonator antenna (DRA) backed by plasma artificial magnetic conductor (AMC) ground plane is designed and optimized for 10-GHz applications. The AMC unit-cell consists of a metal cylinder with two pairs of cuts filled with a noble gas. According to the ionization degree of gas in the two pair of cuts, three polarization states are obtained. The AMC unit-cell operates at 10 GHz with ± 90° bandwidth of 26% and axial ratio (AR) bandwidth span from 9.3 to 10.25 GHz. A linearly polarized (LP) cylindrical DRA backed by 4 × 4 AMC ground plane is investigated. A wide impedance bandwidth of 20%, peak gain 7.8 dBi, and AR < 3 dB of 3.2% are achieved. A parametric study on the AMC unit-cell dimensions is presented. The DRA loaded with optimized AMC unit-cells broaden the AR bandwidth from 9.6 to 10.7 GHz (11%). A 13 × 13 unit-cell perforated dielectric reflectarray loading the DRA is used to increase the total gain. A peak gain of 19.5 dBi is achieved with reconfigurable polarization states. A sequential cooperate feeding network is used with 2 × 2 DRA backed by 8 × 8 AMC unit-cells to improve the gain and CP bandwidth. Two chessboard square and triangle arrangements of AMC unit-cells are investigated. The square arrangement improves AR bandwidth to 2.4 GHz, gain to 13.3 dBi, and side lobe level (SLL) below the main beam to − 12.3 dB. Full-wave simulation is used to study and optimize the proposed structures.

Compact Fabry–Perot Antenna With Wide 3 dB Axial Ratio Bandwidth Based on FSS and AMC Structures

The proposed antenna combines a conventional patch with an artificial magnetic conductor (AMC) ground plane and a frequency selective surface (FSS) superstrate with the height of 0.35 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> (at f = 8.5 GHz) from the feed antenna. In this structure, to create circularly polarized waves, a FSS superstrate composed of an array of quasi-crescent shaped unit cells is used. In addition, to compact the antenna cavity, the AMC ground plane with the reflection phase of zero is utilized. Moreover, for further improvement in the antenna 3 dB axial ratio (AR) bandwidth (BW), an array of diagonal rectangular slots is used in the AMC ground plane. The proposed antenna presents an appropriate 3 dB AR in the whole BW (20%) of antenna with the gain up to 16 dBi. Due to high gain, wideband axial ratio, fabrication simplicity, and compact structure, this antenna is a promising candidate for X-band satellite communication, radar, wireless communication, and microwave power transmission.

Thin-Profile Wideband and High-Gain Microstrip Patch Antenna on a Modified AMC

A low-profile, high-gain, and broadband U-slot cut artificial magnetic conductor (AMC) loaded patch antenna is presented in this letter. The wideband performance is achieved by strategically cutting two rectangular slots and inserting four strips onto a conventional AMC ground plane. Moreover, a defected ground structure is used to reduce the antenna size. As a result, four reflection zeroes are obtained within the antenna | $S_{11}$ | curve. The antenna is characterized by a low profile ( $\boldsymbol{h}/{\boldsymbol{\lambda }_0}\sim 0.05$ , ${\boldsymbol{\lambda }_0}$ is the free-space wavelength at the center frequency), wide bandwidth 58.6%, light weight, low cost, and wide 10 dBi gain bandwidth. The presented antenna is suitable for C-band satellite (3.7–4.2 GHz), 5.15–5.35 GHz WLAN, and the 5G in 3–6 GHz band applications.

Low‐profile wideband Fabry‐Perot resonator antenna using artificial magnetic conductor surface

AbstractA low‐profile, high gain Fabry‐Perot Resonator antenna with a wide operation bandwidth (BW) is presented in this paper. The proposed design consists of an ellipse‐shaped dipole as a wideband radiating source, which is reflected by an artificial magnetic conductor ground plane to achieve low‐profile structure. The antenna gain can be significantly enhanced by the use of a half‐wavelength‐thick dielectric slab as a partial reflecting surface. Additionally, this dielectric slab also contributes to improving the radiation pattern characteristics of the proposed design, especially in the high frequency region. A final prototype with an overall size of 1.2λ L × 1.2λ L × 0.4λ L (λ L is free‐space wavelength at the lowest frequency of 3‐dB gain BW) has been fabricated to validate the concept. The measured results show that the proposed antenna yielded a wide 3‐dB gain BW of approximately 50.3% with a peak gain of 14 dBi and impedance matching BW of 48.9%.

A Compact, Low-Profile Log-Periodic Meandered Dipole Array Antenna with an Artificial Magnetic Conductor

A compact and low-profile log-periodic meandered dipole array (LPMDA) antenna with an artificial magnetic conductor (AMC) is proposed. For compactness, a meander line configuration is implemented with dipole elements and optimized using a genetic algorithm (GA) to realize the LPMDA antenna. As a result, a size reduction of approximately 30% is achieved as compared to a conventional log-periodic dipole array antenna. To enhance the gain characteristics, the AMC ground plane configuration is realized with 9 × 9 unit cells for the LPMDA antenna. Two prototypes of the proposed LPMDA antennas with and without an AMC are fabricated and measured to verify its performance. The measured −10 dB reflection ratio bandwidths are 2.56 : 1 (0.85–2.18 GHz) and 2.34 : 1 (0.92–2.16 GHz) for the proposed LPMDA antennas with and without the AMC, respectively. The gain at the main beam direction within the operating frequency bandwidth is significantly improved from 3.94–7.17 dBi to 7.86–10.01 dBi by applying the AMC.

Reconfigurable, Wideband, Low-Profile, Circularly Polarized Antenna and Array Enabled by an Artificial Magnetic Conductor Ground

A reconfigurable, wideband, and low-profile circular polarization (CP) antenna is presented. Its wideband CP reconfigurability is realized by incorporating RF switches into a cross-bowtie radiator. A compact, wide bandwidth, and polarization-independent artificial magnetic conductor ground plane is developed to minimize the overall profile of the antenna while maintaining its wide bandwidth. The simplicity of this single-element design facilitates the realization of a reconfigurable, wide bandwidth CP array that achieves higher directivity without changing its overall profile. Prototypes of the single element and of a $1 \times 4$ array of these elements were fabricated and tested. The measured results for both prototypes are in good agreement with their simulated values, validating their design principles. They are low profile with a height $\sim 0.05\lambda _{\mathrm {\mathbf {0}}}$ . The array exhibits a wide fractional operational bandwidth: 1.65 GHz (21.7%), and a high realized gain: 13 dBic. Since they would enhance their channel capacity and avoid polarization mismatch issues, these reconfigurable CP antenna systems are very suitable for modern wireless systems.

Wideband Low-Profile Highly Isolated MIMO Antenna With Artificial Magnetic Conductor

A wideband highly isolated multiple-input–multiple-output patch antenna with an artificial magnetic conductor (AMC) ground plane is proposed in this letter. The antenna, which is rotationally symmetrical, is constructed by V-shaped patches coupled by a bowtie dipole. The bowtie dipole and the V-shaped parasitic patches produce two resonant modes that are coupled together. Therefore, a wide impedance bandwidth is obtained. Thanks to the orthogonal feeding and the rotationally symmetrical geometry, the antenna exhibits high port isolation as well as symmetrical radiation patterns with a compact size of 40 × 40 × 1.524 mm3. By placing an AMC ground plane with a distance of 10.5 mm below the radiating element, the antenna can achieve a unidirectional high gain with a lower height of the profile compared to that with perfect electrical conductor ground. Measured results show the antenna has an impedance bandwidth of 31.0% (3.0–4.1 GHz) with port isolation better than 25 dB. The peak gain can reach 7.1 dBi with stable and symmetrical radiation patterns.

Hybrid Genetic Programming for the Development of Metamaterials Designs With Improved Characteristics

The expansion of a hybrid genetic program's (HGP) functionality to allow for the development of broadband two-dimensional metamaterials designs with advanced characteristics is presented. Artificial magnetic conductor (AMC) ground planes and a tunable terahertz absorber generated by the HGP are compared with designs available in the literature. The HGP is shown to produce human-competitive results. The AMC ground planes synthesized by the HGP were found to produce improved results including wider bandwidths and larger reflection coefficient magnitudes than that of the human designs. For one of the designed AMCs, the HGP's bandwidth is 73.3% larger and the minimum reflection magnitude is 1.0% larger than the reference AMC. Similarly, the absorber synthesized by the HGP has larger bandwidths than that of a recently published absorber optimized by random hill climbing. Three bias voltages were tested with the tunable absorber. The bandwidths of the HGP absorber are 23.1%, 37.6%, and 400% larger than the reference absorber, for biases of 4, 2, and 0.5 V/nm, respectively. Four example designs are discussed together with comparative results to illustrate the advantages of the developed HGP-enabled design method.

Spoof Surface Plasmon Polariton Leaky-Wave Antennas Using Periodically Loaded Patches Above PEC and AMC Ground Planes

This paper proposes two spoof surface plasmon polariton (SSPP) leaky-wave antennas using periodically loaded patches above perfect electric conductor (PEC) and artificial magnetic conductor (AMC) ground planes, respectively. The SSPP leaky-wave antenna is based on a SSPP transmission line, along which circular patches are periodically loaded on both sides to provide an additional momentum for phase matching with the radiated waves in the air. The PEC and AMC ground planes underneath the antenna reflect the radiated waves into the upward space, leading to an enhanced radiation gain. Both PEC- and AMC-grounded antenna prototypes are fabricated and measured in comparison with the one without any ground plane. The experimental results show that the PEC and AMC ground planes increase the radiation gain by approximately 3 dB within the operational frequency range 4.5-6.5 GHz. It also demonstrates that the AMC-grounded leaky-wave antenna, with a thickness of 0.08\lambda at 6 GHz, features more compact profile than the PEC-grounded one (with a thickness of 0.3\lambda at 6 GHz).

Gain enhancement of bow‐tie antenna using fractal wideband artificial magnetic conductor ground

A novel fractal wideband artificial magnetic conductor (AMC) structure is designed as the ground plane of a printed bow-tie antenna for gain enhancement and low profile. The origin printed bow-tie antenna is operated in the range from 1.67 to 2.06 GHz for a VSWR <2. The AMC structure consists of 6 × 9 first-order fractal unit cells that are made up of four circles and four smaller circles, and the ±90° reflection phase band is 1.1–3.03 GHz. Both the AMC ground plane and bow-tie antenna are fabricated and measured. The distance between the antenna and the AMC is reduced to one-eighth of the wavelength in free space at 1.7 GHz. The experimental results show that the composite antenna has a wide bandwidth from 1.64 to 1.94 GHz, with a relative frequency bandwidth of 16.7%.

Small artificial magnetic conductor backed log‐periodic microstrip patch antenna

An artificial magnetic conductor (AMC) backed reduced-size log-periodic microstrip patch antenna (LPMA) is presented. To maintain the broadband performance of the LPMA, the AMC ground plane was modified to exhibit a log-periodic structure. Specifically, an AMC ground plane configuration was realised over 0.889 mm thick εr = 10.2 Rogers 6010.2LM substrate for an LPMA printed over 1.524 mm thick εr = 2.94 Rogers 6002 substrate. The AMC-backed LPMA is measured to operate from 5.3 to 8 GHz with linearly polarised broadside radiation, performing with 21% reduced size as compared with a conventional LPMA designed over the identical substrate stack-up.

High-gain antenna using an intelligent artificial magnetic conductor ground plane

We propose a high-gain antenna using an intelligent ground plane composed of artificial magnetic conductors (AMCs). The main role of the ground plane is removing difference in phase delays caused by different path lengths from a signal-feeding dipole onto each AMC cell. Hence, the ground plane consists of AMC cells with different lengths corresponding to the phase delays to be compensated. As a consequence, we can obtain a planar wave front of a reflected wave, which is perpendicular to a boresight direction. By maximizing constructive interference between the reflected waves and direct waves from the dipole, we can significantly increase our antenna gain without deteriorating impedance matching bandwidth behavior. Experimental data has shown good agreement with the prediction, which validates the accuracy and effectiveness of our proposal.

Flexible and Compact AMC Based Antenna for Telemedicine Applications

We present a flexible, compact antenna system intended for telemedicine applications. The design is based on an M-shaped printed monopole antenna operating in the Industrial, Scientific, and Medical (ISM) 2.45 GHz band integrated with a miniaturized slotted Jerusalem Cross (JC) Artificial Magnetic Conductor (AMC) ground plane. The AMC ground plane is utilized to isolate the user's body from undesired electromagnetic radiation in addition to minimizing the antenna's impedance mismatch caused by the proximity to human tissues. Specific Absorption Rate (SAR) is analyzed using a numerical human body model (HUGO) to assess the feasibility of the proposed design. The antenna expresses 18% impedance bandwidth; moreover, the inclusion of the AMC ground plane increases the front to back ratio by 8 dB, provides 3.7 dB increase in gain, in addition to 64% reduction in SAR. Experimental and numerical results show that the radiation characteristics, impedance matching, and SAR values of the proposed design are significantly improved compared to conventional monopole and dipole antennas. Furthermore, it offers a compact and flexible solution which makes it a good candidate for the wearable telemedicine application.

Dual-Band Long-Range Passive RFID Tag Antenna Using an AMC Ground Plane

A dual-band passive radio frequency identification (RFID) tag antenna applicable for a recessed cavity in metallic objects such as heavy equipment, vehicles, aircraft, and containers with long read range is proposed by using an artificial magnetic conductor (AMC) ground plane. The proposed tag antenna consists of a bowtie antenna and a recessed cavity with the AMC ground plane installed on the bottom side of the cavity. The AMC ground plane is utilized to provide dual-band operation at European (869.5 869.7 MHz) and Korean (910 914 MHz) passive UHF RFID bands by replacing the bottom side of the metallic cavity of a PEC-like behavior and, therefore, changing the reflection phase of the ground plane. It is worthwhile to mention that the European and the Korean UHF RFID bands are allocated very closely, and the frequency separation ratio between the two bands is just about 0.045, which is very small. It is demonstrated by experiment that the maximum reading distance of the proposed tag antenna with optimized dimensions can be improved more than 3.1 times at the two RFID bands compared to a commercial RFID tag.

An extremely low-profile offset-fed curl antenna over an AMC ground

Performance of an offset-fed curl antenna over artificial magnetic conductor (AMC) ground planes is investigated.An extensive parametric study is carried out and shown that by proper selection of the AMC ground plane and spiral parameters, a moderate axial ratio and wide impedance bandwidths can be obtained. The performance results for a design example are provided and discussed. The effect of the air gap between the AMC and antenna substrates is also studied and shown that the operating frequency moves to higher frequencies. The results are verified by experiment. The simulation studies were carried out using the finite element software HFSS v10.1. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1036–1041, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25929

PSO를 이용한 주파수 선택 구조 기반 인공 자기 도체 설계

본 논문에서는 주파수 선택 구조를 기반으로 하는 인공 자기 도체 구조를 설계하기 위하여 최적화 알고리즘 중 하나인 particle swarm optimization(PSO) 기법을 이용하였다. 주파수 선택 구조로서 Jerusalem Cross를 갖는 인공 자기 도체의 등가 회로 모델에 PSO를 적용하여, 원하는 공진 주파수 대역을 갖는 최적의 설계값을 얻어낼 수 있음을 확인하였다. 우선 유도한 등가 회로 모델로부터 공진 주파수와 반사 계수 위상 특성을 구하여 상용 소프트웨어로 얻은 값과 일치하는 것을 확인하여 본 논문의 유효함을 확인하였으며, 이로부터 원하는 공진 주파수에 대해 최적화 과정을 통하여 설계 파라미터를 추출하였다. 본 논문에서 유도한 최적화 과정을 이용한 주파수 선택 구조 기반 인공 자기 도체 구조 설계 방법을 이용하여 여러 다른 종류의 주파수 선택 구조 형태를 갖는 인공 자기 도체 구조뿐만 아니라, 인공 자기 도체 구조를 이용한 소형 안테나 접지면 설계 등 마이크로파 회로 설계에 유용하게 사용할 수 있다. In this paper, particle swarm optimization(PSO) is applied for the design of frequency selective surface based artificial magnetic conductor. An equivalent circuit model for this artificial magnetic conductor(AMC) with Jerusalem Cross arrays was derived and then PSO was applied for obtaining the optimized geometrical parameters with desired resonant frequency. The resonant frequency and the reflection phase characteristics from the optimization were compared to the results from commercial software for verifying the validity of this paper. The procedure presented in this paper can be applied to design the AMC with different frequency selective surface and also can be used for the design of microwave circuits like the AMC ground planes.

Design of Planar Artificial Magnetic Conductor Ground Plane Using Frequency-Selective Surfaces for Frequencies Below 1 GHz

A novel design of planar artificial magnetic conductor (AMC) based on a frequency-selective surface (FSS) for frequencies below 1 GHz is presented. A discussion about design parameters and the influence of dielectric substrate permittivity in the operating band and the operating bandwidth is presented. The discussion is supported by a finite element method (FEM) simulation.

Novel Design of a High-gain and Wideband Fabry-Pérot Cavity Antenna Using a Tapered AMC Substrate

A high-gain and wideband electromagnetic bandgap (EBG) resonator antenna with a tapered artificial magnetic conductor (AMC) ground plane is presented. The proposed EBG resonator antenna is comprised of a frequency selective surface (FSS) superstrate with a strip dipole array and an AMC ground plane with tapered rectangular patches. The realized gain and the bandwidth of the antenna can be improved simultaneously by using the tapered AMC where the phase difference of the reflected waves from the patches with different length is within 180° and the destructive interference among them can be considerably reduced. The maximum gain is increased about 2∼3 dB and the bandwidth is improved about 2.5 times compared to when the uniform AMC is used.

Low‐profile platform‐tolerant RFID tag with artificial magnetic conductor (AMC)

AbstractA novel low‐profile (≈0.01λ) platform‐tolerant passive RFID tag incorporated with artificial magnetic conductor (AMC) is proposed in this letter. It consists of a modified dipole antenna combined with an AMC ground plane and a tag chip attached on the feeding point of the antenna. The proposed tag shows long and stable read range from 4 to 6 m with a realized gain ranging from 4.1 to 5.3 dB for different platform materials such as metals and lossy liquids. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2292–2294, 2008; Published online in Wiley InterScience (www.interscience.wiley.com).DOI 10.1002/mop.23690