Vertical Ground Plane Research Articles

A New Configuration Of Broadband Patch Antenna With Circular Polarization For Wireless Power Transmission

An innovative design of a circular polarization antenna for wireless power transmission is described. The suggested antenna is simply constructed, which consists of a square radiating patch having a slotted center with feeding via a probe and an L-shaped ground plane. The application of this L-shaped ground allows a short connection of the probe power supply to the square patch while retaining a certain elevation from the ground plane to the square patch while using an air layer substrate, thereby allows a proper adaptation of the impedance and an improvement of the bandwidth. The purpose of utilizing the slot in the center of the square patch is to create a circular polarization with an axial ratio value of under 3dB. By means of a through-hole through the vertical L-shaped ground plane, the patch radiating can be readily excited with a probe feed pointing into the same plane as the patch. This approach allows to further improve the bandwidth of the circular polarization. In this way, the CP bandwidth of the proposed antenna is significantly extended by about 10% and a good impedance matching over a wide bandwidth is obtained. The features of the proposed design are investigated and optimized using a 3D electromagnetic (EM) solver. It was found that the proposed antenna covers a broad band of 425MHz, has a 3 dB axial ratio CP bandwidth of approx. 85% of the resonant band, and a gain level of 7.4 dBi or more in the bandwidth of the resonant band. Besides the low cost of the proposed antenna arising from its simplest structure, the resulting performance leads the antenna to be a strong candidate among circularly polarized, single element, and single feed patch antennas.

Self-Localization of Mobile Robots Using a Single Catadioptric Camera with Line Feature Extraction.

This paper presents a novel self-localization technique for mobile robots using a central catadioptric camera. A unified sphere model for the image projection is derived by the catadioptric camera calibration. The geometric property of the camera projection model is utilized to obtain the intersections of the vertical lines and ground plane in the scene. Different from the conventional stereo vision techniques, the feature points are projected onto a known planar surface, and the plane equation is used for depth computation. The 3D coordinates of the base points on the ground are calculated using the consecutive image frames. The derivation of motion trajectory is then carried out based on the computation of rotation and translation between the robot positions. We develop an algorithm for feature correspondence matching based on the invariability of the structure in the 3D space. The experimental results obtained using the real scene images have demonstrated the feasibility of the proposed method for mobile robot localization applications.

Characterization of Propagation Phenomena Relevant for 300 GHz Wireless Data Center Links

This article presents details about an extensive channel measurement campaign and subsequent statistical channel models for the characterization of 300 GHz channels for wireless rack-to-rack (R2R) and blade-to-blade (B2B) communications in a data center-like environment. Measurements were conducted in various scenarios such as R2R line-of-sight (LoS), R2R obstructed-LoS (OLoS), R2R reflected-non-LoS (RNLoS), R2R obstructed-RNLoS (ORNLoS), B2B RNLoS, B2B ORNLoS, and B2B LoS scenarios. In the aforementioned scenarios, we explored the impact of transmitter (Tx)/receiver (Rx) misalignment and obstructions such as cables, metal cabinets, and mesh structures on terahertz (THz) propagation, as well as feasibility of using existing metal objects as reflectors for NLoS links. For the R2R LoS scenario, an optical lens was used to extend the Tx-Rx separation distance. This led to a waveguide effect in the channels measured thereby resulting into a path loss exponent (PLE) of 1.48 with a shadowing gain of 0.7 dB. When obstructions of cables are present, ORNLoS link outperforms OLoS link with 2.5 dB lower shadowing gain and weaker multipath. Reflector in the RNLoS link has reflection coefficients very close to 1 for all incident angles. For the B2B scenario, a dual-reflector THz transceiver rack system is proposed to enable wireless links across vertically stacked servers and allow easy maintenance and repair of servers. The measured path loss closely follows the Friis values in the LoS link and in the RNLoS link with hollow vertical ground plane. When obstructions of cables are present, the ORNLoS link experiences 5–10 dB higher path loss and on average 0.25 GHz lower coherence bandwidth than the RNLoS link. The measured statistical channel properties show that the shadowing gain caused by cable clusters follows the log-normal distribution.

A 1-D Tightly Coupled Dipole Array for Broadband mmWave Communication

A wideband phased array antenna for the use in 5G millimeter-wave (mmWave) mobile terminal is presented. The proposed array antenna was designed based on the tightly coupled dipole array (TCDA) technique to achieve a low profile and broadband impedance matching characteristic. Unlike the previously reported TCDAs implemented with 2D arrays on a vertical ground plane, the proposed 1D array antenna exhibited the maximum beam direction parallel to the ground, which is suitable for mobile terminal applications. Using a full-wave electromagnetic simulation tool, a $1\times8$ TCDA was designed on a multilayer substrate including a reflector surface in the middle to replace a vertical ground plane. Prototypes were fabricated and measured with feeding networks designed for 0° and 30° scanning scenarios. The size of the proposed antenna (excluding the feeding network) was $42.3\times 12.05\times0.535$ mm3. The measured bandwidth that subjects to S11 < −10 dB criterion was 22.5–32.5 GHz, which covers most of the worldwide 5G mmWave frequency band candidates at the 20-GHz band range.

Design of Novel Wideband Circularly Polarized Antenna Based on Vivaldi Antenna Structure

This letter presents a novel compact wideband circularly polarized antenna by utilizing Vivaldi antenna structure as the design concept. The proposed antenna consists of four exponentially tapered patches, a circular metal wall and a feed network. Four tapered patches are sequentially rotated and vertically located in the circular metal wall which acts as a vertical ground plane. Slot-coupled feed technique is applied to feed the antenna. Feeding by a corporate feed network, wide impedance bandwidth and axial ratio bandwidth are achieved. Parametric studies are made to optimize the antenna. The experimental results show that the antenna exhibits a 3-dB AR bandwidth of 41.4% (3.45-5.25 GHz) and a 10-dB impedance bandwidth of 57.3% (3.06-5.52 GHz).

A printed dual-wideband magneto-electric dipole antenna for WWAN/LTE applications

A planar-printed dual-wideband U-shaped magneto-electric dipole omnidirectional antenna with a composite feeding structure for WWAN/LTE applications is proposed. Firstly, a U-shaped electric dipole structure is presented to provide a dual-wideband by changing the surface-current distributions. In addition, in order to reduce antenna size and improve impedance matching, a new feeding structure designed with inverted U-shaped tapered line and meandering T-shaped line is introduced. Finally, instead of a conventional vertical ground plane, a small-size one is printed on the reverse side of the substrate to achieve stable gains and omnidirectional radiation patterns. The antenna prototype can attain a bandwidth of 35.8% (0.78–1.12GHz) with a stable gain of 3±0.5dBi for the lower band, and a bandwidth of 50.5% (1.66–2.78GHz) with a gain of 3.8±0.6dBi for the upper band, covering the frequency bands granted for WWAN/LTE systems. To the best of our knowledge, it is the first real-sense planar magneto-electric dipole antenna proposed. In comparison with the existing ME dipole antennas, the proposed antenna, which is planar-printed on a small-size FR4 substrate with a simple structure, can be easily fabricated at low cost and thus is promising for WWAN/LTE communication.

A planar-printed E-shaped omnidirectional magneto-electric dipole antenna for WWAN/LTE applications

A planar-printed E-shaped dual-wideband magneto-electric (ME) dipole antenna for WWAN/LTE applications is proposed. Through changing the surface-current distributions, an E-shaped electric-dipole structure is used to provide a dual-wideband. Besides, to reduce the size of the antenna and improve impedance matching, a novel feeding structure designed with inverted U-shaped tapered line and meandering L-shaped line is introduced. Finally, without conventional vertical ground planes, a small-size one is printed on the back side of the substrate to attain stable gains and omnidirectional radiation patterns. The antenna prototype can attain a bandwidth of 31.6% (0.80–1.10 GHz) with a stable gain of 3.1 ± 0.5 dBi for the lower band, and a bandwidth of 47.5% (1.67–2.71 GHz) with a gain of 3.9 ± 0.7 dBi for the upper band, covering the frequency bands for WWAN/LTE systems. In comparison with the existing ME dipole antennas, the proposed antenna can be easily fabricated at low cost which makes it suitable for WWAN/LTE applications. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1734–1739, 2014

Variations in discharge current waveforms and their power spectra injected from contact discharges of ESD‐gun with different arrangements

AbstractThe International Electrotechnical Commission (IEC) has prescribed an immunity test (IEC61000‐4‐2) of electronic equipment against electrostatic discharges (ESDs), in which a discharge current to be injected onto equipment under test is specified. As for the waveform, however, not the whole waveform but only the rise time, the first peak, and the current amplitudes at 30 and 60 ns are given in the time domain together with their uncertainties, which are required to check on the condition that an ESD generator (ESD‐gun) shall be arranged vertically to an IEC‐recommended calibration target and its earth return wire is kept away as far as possible from a vertical ground plane (IEC standard arrangement). In this study, to clarify how arrangements of an ESD‐gun and its earth return wire affect discharge currents, we measured discharge current waveforms for contact discharges of an ESD‐gun onto an IEC calibration target with respect to various inclinations of the ESD‐gun and arrangements of its earth return wire, and also calculated their current power spectra normalized to that of the discharge current for the IEC standard arrangement. As a result, we found that inclinations of the ESD gun affect the first peak current, which increases current power spectra by 14 dB at frequencies over 300 MHz, and that arrangements of the return wire influence the current waveforms between the first and second peaks, which provides variations in power spectra by ±12 dB in the frequency range from 10 MHz to 200 MHz. This finding suggests that arrangements of an ESD‐gun and its earth return wire are likely to cause different immunity test results. It was also found that in comparison with measured discharge currents for the standard arrangement, the calculated waveform of a discharge current from a formula, which has been included in the recent standard, has a more gentle falling waveform, and produces power spectra of +15 dB in the frequency range from 10 MHz to 200 MHz and –12 dB at frequencies over 300 MHz. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 180(1): 9–14, 2012; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.21270

Evaluation of Dielectric Resonator Sensor for Near-Field Breast Tumor Detection

An H-shape ultrawideband (UWB) dielectric resonator (DR) mounted on a vertical ground plane edge with broadside radiation patterns is evaluated for breast tumor detection. In order to scan the whole breast, the proposed DR sensor can be attached to the skin without a need for matching medium. The sensor has a wide half power beamwidth, therefore path loss is reduced. In addition, the DR sensor provides very good pulse-preserving performance such as low distortion and constant gain characteristics with high efficiency. The small footprints of the sensor over the skin allows for more sensors nearby or in contact with the breast skin. Suitability of the compact DR sensor for breast tumor detection can be seen from frequency domain analyses as well as time domain analyses. Accurate tumor response is obtained due to the compact size and very good sensor characteristics.

Variations in Discharge Current Waveforms and its Power Spectra Injected from Contact Discharges of ESD-Gun with Different Arrangements

The International Electrotechnical Commission (IEC) has prescribed an immunity test (IEC61000-4-2) of electronic equipment against electrostatic discharges (ESDs), in which a discharge current to be injected onto equipment under test is specified. As for the waveform, however, not the whole waveform but only the rise time, the first peak, and the current amplitudes at 30 ns and 60 ns are given in the time domain together with their uncertainties, which are required to check on the condition that an ESD generator (ESD-gun) shall be arranged vertically to an IEC recommended calibration target and its earth return wire is kept away as far as possible from a vertical ground plane (IEC standard arrangement). In this study, to clarify how arrangements of an ESD-gun and its earth return wire affect discharge currents, we measured discharge current waveforms for contact discharges of an ESD-gun onto an IEC calibration target with respect to various inclinations of the ESD-gun and arrangements of its earth return wire, and also calculated their current power spectra normalized to that of the discharge current for the IEC standard arrangement. As a result, we found that inclinations of the ESD gun affect the first peak current, which increases current power spectra by 14 dB at frequencies over 300 MHz, and that arrangements of the return wire influence the current waveforms between the first and second peaks, which provides variations in power spectra by ±12 dB in the frequency range from 10 MHz to 200 MHz. This finding suggests that arrangements of an ESD gun and its earth return wire are likely to cause different immunity test results. It was also found that in comparison with measured discharge currents for the standard arrangement, the calculated waveform of a discharge current from a formula, which has been included in the recent standard, has a more gentle falling waveform, and produces power spectra of +15dB in the frequency range from 10 MHz to 200 MHz and -12 dB at frequencies over 300 MHz.

Ultrawideband Dielectric Resonator Antenna With Broadside Patterns Mounted on a Vertical Ground Plane Edge

A novel portable dielectric resonator antenna (DRA) design with broadside radiation is presented for ultrawideband wireless applications and narrow pulse sensor for breast cancer detections. The antenna provides broadside radiation. By using a solid rectangular dielectric resonator mounted on a vertical ground plane edge, the total antenna volume is considered to be less than that with a perpendicular ground plane. A wide impedance matching bandwidth is achieved. In addition, a modified version of the rectangular dielectric resonator antenna, which has two dielectric pieces removed to have an A-shaped resonator, provides wider impedance matching bandwidth of around 93% with much better broadside radiation characteristics and lighter weight is also considered. Comparison between the two antennas is presented with parametric study. The modified antenna is built and tested and very good agreement between computed and measured results is obtained.

Conformal Antennas on Liquid Crystalline Polymer Based Rigid-Flex Substrates Integrated With the Front-End Module

Recent developments in liquid crystalline polymer (LCP)-based processing technology have shown that highly-integrated, fully-packaged radio-frequency (RF) front-end modules with high-performance can be designed by using the system-on-package (SOP) approach. However, the direct integration of a large antenna element to a small module package still remains an issue. This paper presents a novel conformal antenna structure, which results in a compact integration of the antenna and the module package for 5 GHz WLAN/WiMAX applications. The extension of 5 GHz single-band operation to 2.4/5 GHz dual-band operation is also discussed in this paper. The antenna is an inverse L-shaped monopole printed on a 25-mum-thick flexible LCP layer, which protrudes from a rigid multilayer organic substrate. The shielding effects of a grounded metal case, which can house the associated module circuitry, are also considered during the design process. The metal case serves as a vertical ground plane for the antenna in addition to protecting the module circuitry from the near-fields of the antenna. The flexible LCP substrate can be bent and folded over the module case, resulting in a compact design and the tight integration of the antenna with the front-end module. The details of the design and the fabrication of the proposed structure as well as the simulation and the measurement data are presented in this paper.

An internal multiband antenna for WLAN and WWAN applications

AbstractIn this letter, we propose a novel multiband antenna which can be integrated into a laptop computer for WLAN and WWAN applications. The antenna, evolved from a dual‐band inverted‐F antenna, is mounted on the top‐edge of a vertical ground plane of LCD panel. By adding four parasitic resonators which are short‐circuited quarter‐wavelength elements, the antenna can achieve wideband performance to cover GSM850/GSM900/DCS/PCS/UMTS and 802.11a/b/g. A simulation was performed by HFSS to optimally design the antenna, and then a practical structure was also fabricated to verify the simulation results. The measured antenna parameters as well as the radiation efficiency are presented to validate the proposed antenna. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1803–1807, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24501

수직 접지면을 가지는 4중 대역용 이중 스파이럴 라인 로디드 모노폴 안테나

본 논문에서는 수직 접지면을 가지는 4중 대역용 이중 스파이럴 라인 로디드 모노폴 안테나를 제안한다. 안테나의 크기는 <TEX>$38{\times}12{\times}7\;mm^3$</TEX>이고, 접지면의 크기는 <TEX>$40{\times}92\;mm^2$</TEX>이다. 측정된 안테나의 대역폭은 <TEX>$VSWR{\le}2$</TEX>를 기준으로 첫 번째 대역과 두 번째 대역에서 각각 11.7 %와 24.8 %이며, Cellular(<TEX>$0.824{\sim}0.894\;GHz$</TEX>), PCS(<TEX>$1.750{\sim}1.870\;GHz$</TEX>), UMTS(<TEX>$1.920{\sim}2.170\;GHz$</TEX>) 그리고 IMT-2000(<TEX>$1.885{\sim}2.200\;GHz$</TEX>) 대역을 동시에 수용한다. 측정된 안테나의 최대 이득은 Cellular, PCS, UMTS, IMT-2000 대역의 중심 주파수에서 -0.99 dBi, 4.07 dBi, 2.72 dBi와 4.33 dBi이다. In this paper, we propose a dual-spiral line loaded monopole antenna having a vertical ground plane for quadband applications. The antenna occupies a volume of <TEX>$38{\times}12{\times}7\;mm^3$</TEX> with a <TEX>$40{\times}92\;mm^2$</TEX> ground plane. The measured impedance bandwidths of the antenna based on <TEX>$VSWR{\le}2$</TEX> are approximately of 11.7 % and 24.8 % in the first and second frequency band, respectively. The operating frequency can simultaneously cover Cellular(<TEX>$0.824{\sim}0.894\;GHz$</TEX>), PCS(<TEX>$1.750{\sim}1.870\;MHz$</TEX>), UMTS(<TEX>$1.920{\sim}2.170\;MHz$</TEX>), and IMT-2000(<TEX>$1.885{\sim}2.200\;GHz$</TEX>) bands. The maximum gains of the antenna are -0.99 dBi, 4.07 dBi, 2.72 dBi, and 4.33 dBi at the center frequencies of the Cellular, PCS, UMTS, and IMT-2000 bands, respectively. Good radiation patterns are experimentally obtained.

A compact spiral stripline‐loaded monopole antenna with a vertical ground plane

AbstractIn this letter, we propose a compact spiral stripline‐loaded monopole antenna on a vertical ground plane. The measured results show that the antenna has a fractional bandwidth of 12.1% for a voltage standing wave ratio (VSWR) less than 2 at the center frequency of 1.10 GHz, as well as a good omni‐directional radiation pattern. The small size of 0.04 λo × 0.04 λo × 0.04 λo makes it promising for use as an internal antenna in mobile handsets. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 250–252, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23043

Small broadband disk‐loaded monopole antenna with a vertical ground plane

AbstractA small broadband monopole antenna with a vertical ground plane and an electromagnetically coupled feed is presented in this paper. The antenna was formed by positioning a probe with a folded stripline under a shorted square disk. A resonance of the shorted square disk was coupled to a resonance of the probe with a folded stripline, so that the antenna had a wide bandwidth of about 37% at the center frequency of 2.313 GHz based on a VSWR ≤ 2. The antenna had dimensions of 11 mm × 11 mm × 11 mm and rectangular slits were inserted into the vertical ground plane to improve distortion of the radiation pattern. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1401–1405, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI.10.1002/mop.22422

Wideband EMC chip antenna for WLAN/WiMAX operation in the sliding mobile phone

AbstractA wideband electromagnetic‐compatible (EMC) chip antenna for application in the sliding mobile phone for WLAN/WiMAX dual‐network operation is presented. The proposed EMC antenna is easily fabricated by mounting a metal pattern onto a foam base of 30 × 6 × 6 mm3. The metal pattern comprises a radiating portion and a vertical ground plane. The radiating portion further consists of a shorted driven strip and a shorted parasitic strip, both of them together generating a wide bandwidth for 2.4‐GHz WLAN operation (2400–2484 MHz) and 2.5‐GHz WiMAX operation (2500–2690 MHz). The vertical ground plane functions as an effective shielding wall and allows the antenna to be in direct contact with nearby electronic components or conducting elements. Small variations on the performances of the proposed antenna for the sliding mobile phone in the slid‐open (talk) and standby conditions are also obtained. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1362–1366, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21657

An internal planar mobile-phone antenna with a vertical ground plane

An internal planar mobile phone antenna with a small vertical ground plane electrically connected to the system ground plane of the mobile phone is presented. The vertical ground plane can function as an effective shielding wall between the antenna and the nearby RF-shielding metal case or other associated elements in a mobile phone. In this case, the internal antenna can be compactly integrated within the mobile phone without degradation of the antenna performances. This vertical-ground design concept applied to an internal PIFA with a hollow shorting cylinder for a UMTS mobile phone is studied. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 46: 597–599, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21061

A circular planar inverted‐L antenna with a vertical ground plane

AbstractA new broadband planar inverted‐L antenna (PILA) with a vertical ground plane (VGN) is experimentally presented. With the electromagnetic coupling between the radiator and VGN, the 2:1 VSWR impedance bandwidth of &gt; 45% has been attained. The radiation patterns similar to those of conventional planar inverted‐ L or F antennas are applicable for land mobile communication systems. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 315–317, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10594

Influence of a ground plane on the ESD event in electronic systems

Capacitance coefficients were measured for a basic two-conductor system, simulating the approach of a charged object (the human body) to a second object which can be floating or grounded (the equipment under test). Parameters studied include the size of the conductors, their separation, and position relative to vertical and horizontal ground planes. System equations, based on Maxwell's technique, are solved to yield the body potentials and a relative probability of discharge for the various configurations. The presence of ground planes is shown to increase the ESD (electrostatic discharge) susceptibility of small floating bodies. The results provide a better understanding to the ESD event and demonstrate the importance of ground planes in electrostatic discharge test methods. >