Electromagnetic Bandgap Microstrip Research Articles

Compact hybrid EBG microstrip antenna for wearable applications

Abstract A novel strip line fed, circularly polarized (CP), annular slotted dual band antenna using hybrid electromagnetic band gap (EBG) structure for Global Positioning System (GPS) has been herein designed, analyzed, and investigated for wearable applications. Adjusting the radii of the annular slots on the radiating patch excellent circular polarized (CP) radiation and impedance matching is achieved. The design demonstrates Kapton based flexible, robust, and low-profile solution with permittivity of 3.4 to meet the requirements of wearable applications. Due to the high losses of the animal body, the electromagnetic band gap (EBG) structure is used to reduce back radiation and the effect of frequency detuning. The proposed antenna structure also enhances the front-to-back ratio (FBR) by 10 dB. This antenna with dimensions 0.56λ 0 × 0.4913λ 0 × 0.002λ 0 analyzed using a flexible Kapton substrate. Optimized hybrid EBG structure provides an excellent Specific Absorption Rate (SAR) along with all other antenna parameters, within acceptable for GPS-based wearable applications at 1.13 GHz and 1.157 GHz frequency band. Therefore the proposed antenna is a suitable candidate for GPS-based tracking and wireless body area network (WBAN) applications. The proposed antenna was also tested upon fabrication and the measured results agree with simulated results.

Single Band EBG Antenna for Wireless Power Transfer Applications

This work demonstrates the design of a single band Electromagnetic Band Gap (EBG) antenna by employing an open stub EBG microstrip of a patch antenna for better achievements in terms of its performance to be utilized in a reconfigurable harvester to operate over a wide input power range. The EBG antenna has been used to gather RF energy and a FET-transistor has been obtainable to determine and control the power flow with the intention to operate at the same time for a different level of input power. The measured data of the EBG antenna shows a directivity of 8.52 dBi, a gain of 7.18 dBi, a return loss of −27 dB with a radiation efficiency of 84.3%, showing a clear enhancement in directivity, peak realized gain, and radiation efficiency by 41.76%, 25.61%, and 17.12% respectively compared with a regular reference antenna; without utilized the EBG structure. Moreover, the harvester design accomplishes 40% of RF-DC power conversion efficiency over a wide dynamic input power range from −15 to 27 dBm, and its peak is around 78%. The harvester is designed to work at the ISM band for 915 MHz and is suitable for Wireless Power Transfer (WPT) uses.

Analysis and Development of an Efficient Cross-Slot Loaded Compact Electromagnetic Band Gap Antenna

This paper is devoted to a novel Electromagnetic Band Gap (EBG) single-feed circularly polarized microstrip EBG antenna with compact size proposed for C-Band applications. The antenna structure will include eight slits introduced at the boundary and the corners in the radiating square patch with a cross-slot at the center. The provided study will effectively approve the various proposed structures and interest occupied by these types of antennas in the enhancement of output parameters (gain, directivity, radiation efficiency, and bandwidth) without much affecting the operating bandwidth at C-band. At first, the concept and the realization of a directive and circularly polarized antenna using an electromagnetic band gap material whose circular polarization is generated by the structure itself is discussed. The analysis and simulation results are presented for an antenna operating at 6.1 GHz using computer Simulation Technologies (CST). Furthermore, the new compact circular polarized EBG antenna, compared to experimental results, will confirm the pre-studied goal of these kinds of antennas such as radiation efficiency, polarization purity, radiation efficiency, high directivity, and gain.

New electromagnetic band gap antenna for multiple ultra wide band applications

This paper presents a compact multiband microstrip electromagnetic band gap (EBG) patch antenna with partial ground used for the 2nd and 3rd mode excitation, allowing multiple band resonance and control of the resonance frequencies. The electromagnetic band gap elements are inserted to improve obviously output parameters (gain directivity, return loss, maximum radiation Intensity, and radiation efficiency). Simulation and measurement results show a multiband antenna WiMAX, WLAN-band applications that can effectively cover three separated bandwidths (2.12, 3.1 and 5.41 GHz). The proposed compact antenna is grounded on a 1.6 mm-thick FR4 epoxy substrate with overall dimension of 0.305λ × 0.305λ × 0.012λ at lower frequency. The whole size of the proposed antenna with an overall area of 25 × 38 × 1.6 mm3 is maintained, and a low cross-polarization level within the operating frequency range. Electromagnetic Band Gap materials, artificially engineered structures, have the main role to improve the output performance of the patch antennas.

Mismatch in EBG Common-Mode Filters Implemented on PCBs

In this article, impedance mismatch effects on the characteristics of common-mode (CM) electromagnetic bandgap (EBG) filters are studied using three-dimensional (3-D) full-wave numerical simulations. The CM EBG filters considered herein are designed using standard printed circuit board technology and contain either microstrip (MS) differential pairs running above the EBG plane, or stripline (SL) differential pairs running on one of the layers next to the EBG plane. First, the terminations are fixed at 50 Ω, and the effects of the differential line impedance variations on the EBG filter parameters are studied. Overall, the considered variations in the widths of the traces and edge-to-edge separation distances in both the MS and SL structures do not drastically deteriorate the performance of the EBG CM filters. Then impedances of the ports are set different from 50 Ω, and the effects of this mismatch on the baseline SL and MS EBG structures are studied. It is shown that lower port impedances may have significant effect on the characteristics of filters. In addition, baseline EBG filters are cascaded with unmatched four-port load, and this may also deteriorate performance of filters.

New triple band electromagnetic band gap microstrip patch antenna with two shaped parasitic elements

This paper presents a triple band microstrip electromagnetic band gap (EBG) patch antenna with two shaped parasitic elements used for 2nd and 3rd mode excitation, permitting multiple band resonance and control of the resonance frequencies. Simulation and measurement results show triple-band (S/C/X-band) antenna applications that can effectively cover three separate bandwidths: 3.79 GHz for moderate range surveillance, terminal air traffic control, long-range weather, marine radar; 7.5 GHz that satisfy the requirements of the C-band applications specific for long-distance radio telecommunications; 11.8 GHz that satisfy the requirements for X-band applications destined for satellite communications, radar, terrestrial broadband, space communications, amateur radio, molecular rotational spectroscopy. The main characteristics of the proposal is its ability to increase the gain, directivity, return loss and the total efficiency of the antenna without affecting the geometric parameters, which makes the designed antenna applicable for a wide range of radio frequency devices operating at the chosen resonance frequencies. The simulated results using computer simulation technology 2014 compared to experiment have demonstrated attractive performance such good impedance matching, compact features (light weight, small sized, low cost), and rigidness compared to other classic antennas.

Microfluidic EBG Sensor Based on Phase-Shift Method Realized Using 3D Printing Technology.

In this article, we propose a novel microfluidic microstrip electromagnetic band gap (EBG) sensor realized using cost-effective 3D printing technology. Microstrip sensor allows monitoring of the fluid properties flowing in the microchannel embedded between the microstrip line and ground plane. The sensor’s operating principle is based on the phase-shift method, which allows the characterization at a single operating frequency of 6 GHz. The defected electromagnetic band gap (EBG) structure is realized as a pattern in the microstrip ground plane to improve sensor sensitivity. The designed microfluidic channel is fabricated using a fused deposition modelling (FDM) 3D printing process without additional supporting layers, while the conductive layers are realized using sticky aluminium tape. The measurement results show that the change of permittivity of the fluid in the microfluidic channel from 1 to 80 results in the phase-shift difference of almost 90°. The potential application is demonstrated through the implementation of a proposed sensor for the detection of toluene concentration in toluene–methanol mixture where various concentrations of toluene were analysed.

A laser-assisted process to produce patterned growth of vertically aligned nanowire arrays for monolithic microwave integrated devices

An experimental process for the fabrication of microwave devices made of nanowire arrays embedded in a dielectric template is presented. A pulse laser process is used to produce a patterned surface mask on alumina templates, defining precisely the wire growing areas during electroplating. This technique makes it possible to finely position multiple nanowire arrays in the template, as well as produce large areas and complex structures, combining transmission line sections with various nanowire heights. The efficiency of this process is demonstrated through the realisation of a microstrip electromagnetic band-gap filter and a substrate-integrated waveguide.

Analysis of Resonant Frequency for Electromagnetic Bandgap Structure Based on Phase Coherence

A new method based on phase coherence for resonant frequency analysis of the electromagnetic bandgap (EBG) structure is proposed in this paper. Based on a simplified analysis model of reflected and transmitted waves, the resonant frequencies of reflection coefficient for two-unit cells are achieved through the phase of transmission coefficient for one-unit cell. For the purpose of method verification, a microstrip EBG structure is simulated and measured, which shows great consistence of resonant frequency between phase coherence method analysis and actual simulation/measurement. Since the proposed method explains the resonance of EBG structure from the interference of electromagnetic waves level, it has a clear physical meaning. Moreover, it may provide a convenient way for the characteristic analysis of EBG structure.

Transmission resonant frequency and its amplitude prediction for ebg structure based on phase coherence

AbstractA new method based on phase coherence is proposed for the strengthened resonant transmission frequency and its amplitude prediction. This method has a clear physical meaning and great convenience. A microstrip electromagnetic bandgap structure is used to verify the method, and both the simulated and measured results demonstrate its validity. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:409–412, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26570

Planar rat-race coupler with microstrip electromagnetic bandgap element

This article presents the design of microstrip electromagnetic bandgap element and its applications in the planar rat-race hybrid coupler with the purpose of harmonic suppression and size reduction.The measured results of proposed hybrid coupler with 1.25 GHz central frequency verify its attractive performance with an insertion loss of less than 3.4 dB, a return loss of about 20 dB, an isolation of 32 dB, 17 dB suppression for the second harmonic, 25 dB suppression for the third harmonic, and 22 dB suppression for the fourth harmonic. In particular, with no loss of the performance, the area of proposed rat-race coupler, achieving 57% save in size, has been successfully reduced from 38.82 cm2 (the area of conventional hybrid coupler) to 16.72 cm2. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:2619–2622, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26308

1D Koch fractal electromagnetic bandgap microstrip structures with r /a ratios higher than 0.5

A 1D Koch fractal electromagnetic bandgap (KFEBG) microstrip structure is proposed.It is conceived by replacing the conventional holes etched in the ground plane of a microstrip line by level-1 Koch fractal cell geometries, which have been obtained from a hexagonal shape. In the case of the conventional 1D electromagnetic bandgap (EBG) microstrip structure with periodic hole pattern, the design is limited to r/a ratios lower than 0.45, whereas the proposed pattern allows achieving r/a ratios higher than 0.5. It is shown that the conventional EBG and KFEBG microstrip structures behave as a stopband filter as r/a 0.5 can be useful for the design of low-pass filters. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:646–649, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25763

Susceptibility of an Electromagnetic BandGap Filter

In a compact dual-planar electromagnetic (EM) bandgap (EBG) microstrip structure, patches are etched periodically in the ground plane to prohibit the propagation of EM waves in certain frequency bands so as to provide filtering functionality. However, the existence of the etched patches in the ground plane becomes a concern in terms of EM compatibility (EMC) and EM susceptibility (EMS). These structures might be prone to EM interference from nearby circuit components as compared to a microstrip filter with a perfect ground plane. In this paper, we study the EMS of a dual-planar EBG filter structure to a microstrip line in close proximity. This study examines the coupling effects of a nearby microstrip line on the performance of the EBG structure when the microstrip line is transmitting a signal and when it is not transmitting a signal. When the microstrip line is transmitting a signal, the effects of the working frequency and the direction of the signal on the coupling to the EBG structure are studied. Experimental and numerical work are presented, analyzed, and verified. The results obtained are useful for the applications and integrations of EBG microstrip structures to microwave circuits. They are useful for EMC and EMS studies of other patterned ground structures/defected ground structures.

Fast and accurate calculation of transmission coefficients for an EBG microstrip structure

AbstractIn this article, an approach is proposed to provide an accurate and fast calculation on the transmission coefficients of an electromagnetic band‐gap (EBG) structures where patches are periodically inserted into the microstrip line (capacitive loaded EBG microstrip structure). The stopband performance, such as the center frequency, bandwidth, and attenuation, of these EBG structures can be predicted at a high degree of accuracy through the calculation of the transmission coefficient. The dispersion relation of electromagnetic waves in the structure is derived, plotted, and analyzed. The grating nature of the structure is demonstrated. This approach can be applied to periodic microstrip structures of a similar nature to simplify the analysis and design procedures. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:793–797, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25046

RF RAT-RACE COUPLERS WITH U-TYPE DGS MICROSTRIP ELECTROMAGNETIC BAND GAP ELEMENT

In this letter, an investigation of a novel compact rat-race hybrid coupler incorporating a U-type defected ground structure (UDGS) is presented. Served by this microstrip electromagnetic band gap element (MEBE) technology, the size of the coupler is reduced due to its slow-wave effect and its band-stop effect enables strong high-order harmonics rejection. In the meantime, the measured performance of the proposed coupler is comparable to that of a conventional microstrip hybrid coupler. This miniaturization and harmonic suppression technology has great potential application in MICs and MMICs to reduce circuit size, lower material cost and improve the overall performance of wireless communication systems.

MINIATURIZED AND HARMONIC-SUPPRESSED RF WILKINSON POWER DIVIDER WITH IB-CMRC

In this paper, the technique served by a microstrip electromagnetic band gap cell entitled IBCMRC is employed to suppress the high-order harmonics and reduce the length by over 30% for a quarter-wave conventional transmission line. The successful application of IB-CMRC cell in a 2 GHz Wilkinson power divider shows that the second and third harmonics are successfully suppressed without downgrading the performance at the operating frequency. The whole size of the proposed IBCMRC-based divider has been reduced by 42% compared to the conventional divider. In miniaturization and harmonic rejection of microwave circuits, the proposed IBCMRC technique holds great promise.

Miniaturized and harmonics‐rejected slow‐wave branch‐line coupler based on microstrip electromagnetic bandgap element

AbstractThis article presents a planar branch‐line hybrid coupler with an effective technique for harmonic suppression and size reduction. The proposed technique served by a microstrip electromagnetic bandgap element entitled MEBE (compact microstrip resonant cell) is used to suppress the harmonics and reduce the length of a quarter wavelength line when compared with the conventional branch‐line coupler. The planar structure enables an easy circuit implementation in printed circuit boards without any additional process and lumped elements. From the measured results, better than 30 dB suppression for the second harmonic and 18 dB suppression for the third harmonic are obtained while maintaining the characteristics of conventional branch‐line hybrid coupler. It is able to achieve two insertion losses of less than 3.5 dB, the return loss of 18 dB, and isolation of 19 dB at operating frequency. With our improved beeline compact microstrip resonant cell, compact branch‐line coupler occupying areas of 35.86% relative to conventional designs has been realized. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1080–1084, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24241

MICROSTRIP ELECTROMAGNETIC BANDGAP ELEMENT ON GROUND FOR HYBRID RING COUPLERS

In this paper, a novel compact rat-race hybrid coupler incorporating square open-loop defected ground structures (SOL-DGSs) is designed and verified. As a new wave of microstrip electromagnetic bandgap element (MEBE) technology on ground plane, the bandgap characteristic of SOL-DGS is employed to reject the high-order harmonics without any additional filter and the excellent slow-wave effect of SOL-DGS is studied and utilized to reduce the circuit size in the design of the hybrid coupler. The measured insertion losses are 3.54 dB and 3.63 dB for two input ports. The isolation between port 1 and port 3 achieves around -30 dB. Furthermore, the proposed rat-race coupler successfully rejects the second, third, fourth and even fifth harmonic signals.

A COMPACT BALUN BASED ON MICROSTRIP EBG CELL AND INTERDIGITAL CAPACITOR

A novel compact balun (balanced-to-unbalanced) that consists of a low-pass network served by a microstrip electromagnetic bandgap (EBG) cell and a high-pass …-network formed with an interdigital capacitor is presented. This proposed approach can efiectively operate the compact balun without the use of ‚=4 microstrip lines to reduce the circuit area over 50% compared to the conventional Marchand balun. The core dimension of the compact balun is 0:74cm£0:7cm. The planar structure enables an e-cient circuit design in printed circuit boards (PCB) without using any bonding wires, defected ground structures (DGS), or surface mounted devices (SMD). A compact balun operating in the 3GHz band has been implemented in a FR-4 PCB. From the measured results, the return loss of the input port is better than 15dB over the band from 2.6 to 4GHz. The amplitude and phase imbalances are less than 1.4dB and 3 - with the 20% operational bandwidth ranging from 2.7 to 3.3GHz, respectively.

A Novel Compact Spiral Electromagnetic Band-Gap (EBG) Structure

A novel compact electromagnetic band-gap (EBG) structure in a spiral shape is presented and investigated. This structure significantly enlarges the capacitance between neighboring elements. The simulations and experimental results have proved that the size of the spiral structure is only 30.9% of the conventional EBG structure. Two applications have been shown, including patch antenna with the spiral EBG structure and a double-element microstrip antenna array with low mutual coupling. The measured results show that a gain improvement over 3 dB and a significant reduction of cross polarization in H-plane are obtained. A 6 dB reduction of mutual coupling is achieved in a double-element EBG microstrip antenna array.