Ground Plane In Order Research Articles

The analytical model of time-harmonic electric field and impedance spectrum in the multilayered interdigital electrode structure

Accurately determining the time-harmonic electric field and impedance spectrum in the multilayered interdigital electrode (IDE) transducers with lossy dielectrics is essential for the design of the structure, the property estimation of the dielectric, and performance optimization. This paper presents an analytical model of the electric field and impedance within a multilayered interdigitated electrode (IDE) when subjected to alternating excitation through the method of separation of variables (MSV). The equivalent circuit of IDE is established, where the impedance is the parallel of capacitive coupling and resistive coupling between electrodes. The general solutions for the electric field and impedance involving arbitrary numbers and complex permittivities of the dielectric layers are analytically derived. However, due to the approximation of boundary conditions, these physical quantities cannot be accurately obtained by the conventional analytical method using conformal mapping technique (CMT) and partial capacitance technique (PCT). The proposed model exhibits proficiency in generating precise electric field images and impedance values that closely correspond with simulated data, even when accounting for the frequency-dependent characteristics of permittivity and conductivity in lossy dielectrics. Moreover, the approaches to improve the sensitivity of a traditional three-layered IDE-based sensor are demonstrated. For a three-layered IDE-based capacitive sensor, improving the sensitivity can be accomplished through the incorporation of a ground plane at the substrate's bottom and increasing the metallization rate. Conversely, it is recommended to reduce the metallization rate, increase substrate thickness, and remove the ground plane in order to enhance the sensitivity of the IDE-based impedance sensor. The experimental results demonstrate that the proposed model generates outstanding impedance spectra (involving capacitance spectra and resistance spectra) results for various metallization ratios and top layers. This exemplifies the model's potential for predicting, designing, and enhancing a complex multilayered IDE-based transducer to achieve precise and sensitive detection.

Analysis of a Compact Electrically Small Antenna with SRR for RFID Applications

This paper contains the design and analysis of a compact, bidirectional Electrically Small Antenna (ESA) at 0.9 GHz for Radio Frequency Identification (RFID) and a global system for mobile communication applications. The proposed design consists of a microstrip patch antenna enclosed inside the split ring resonators, in which a split ring resonator was subtracted from the ground plane in order to obtain the results at lower frequencies by maintaining a compact size. This ESA was designed on FR4 substrate having a dimension of 30 mm × 30 mm × 1.6 mm. This antenna was created and simulated with the Ansys HFSS. The ESA was fabricated by chemical etching and it was measured with the MS2037C Anritsu Combinational Analyzer. The simulated results show that the ESA attains a bandwidth of 100 MHz (with S11 < -10 dB) at 0.9 GHz. The bidirectional radiation pattern in both H and E planes with a radiation efficiency of 80% at the resonant frequency was obtained. A close agreement of 90% between the simulated and the measured results was observed.

A Dual-Polarized MIMO Array Antenna System for Future Smartphone

In this paper, a dual-polarization four antennas Multiple Input Multiple Output (MIMO) scheme is proposed. The four elements are arranged over a surface area of 67×139mm2 printed circuit board (PCB) using dielectric substrate FR-4 with epsilon 4.4 and thermal conductivity 0.025. A circular slot radiator is etched in ground plane in order to improve the radiation characteristics. To mitigate the mutual coupling in the proposed MIMO scheme, two rectangular parasitics with one open rib are embedded across square slot radiator. The proposed single antenna model covers a frequency range of 5.81-6.66 GHz at -10dB impedance bandwidth. However, the bandwidth is raised up to 1.47 MHz (5.48-6.95) GHz at -6dB. The results show that -20 dB return losses can be obtained, while -45 dB isolation was achieved for a dual microstrip line. The proposed antenna can be integrated with new smart-mobile devices for future 5G wireless communications.

A Compact Dual-Band CPW-Fed MIMO Antenna for Indoor Applications

A compact dual-band multiple-input-multiple-output (MIMO) antenna for LTE700, GSM1900, and UMTS applications with high isolation is presented. To enhance impedance matching and multiband operation, two inverted L-shaped monopoles are printed in the circular slot of the ground plane. The single element design is mirrored along the diameter of the circular slot of the ground plane. A strip is employed between the two radiators in order to mitigate the mutual coupling effect and enhance the impedance matching at operating bandwidths. Moreover, two slits are inserted in the ground plane in order to disturb the current distribution between radiating elements, and hence, the isolation between elements is improved. The measured 10 dB return loss bandwidth is 100 MHz (698–798 MHz) and 359 MHz (1765-2124 MHz) over the LTE700, GSM1900, and UMTS bands. The measured isolation between the two ports is less than -13 dB over the LTE700 bands while it is recorded to be less than -17 dB over the GSM1900 and UMTS bands. In addition, parametric studies of the proposed MIMO antenna are performed, and the surface current analysis is discussed to show the effect of the isolation structure. The radiation patterns are measured, and envelope correlation coefficient is calculated. The simulated results are in good agreement with measurements.

Circularly polarised patch array antenna based on reactive impedance surface

In this study, a circularly polarised (CP) patch array antenna based on reactive impedance surface (RIS) is presented. The proposed 4 × 4 patch array antenna possesses a RIS layer which is utilised to replace the conventional ground plane in order to enhance the bandwidth. Meanwhile, patches are cut with two diagonal corners and a rectangular slot for the fulfilment of wideband CP radiation and fed by a one-to-sixteen network simultaneously. Furthermore, in order to explain the effect of RIS in the axial ratio (AR), the CP antenna elements with (or without) RIS are designed. There is the same trend in simulated and measured results. Measured results show the proposed antenna exhibits good performances, such as wideband impedance matching, low AR, high gain. It is testified that pure CP radiation and symmetry broadside patterns are achieved in a wide frequency band, indicating the proposed antenna can exhibit significant application in global satellite communication systems and 5G Wi-Fi application.

Size miniaturization of microstrip antenna embedded with open-ended ground slots

A compact rectangular microstrip antenna embedded with open-ended ground slots is presented in this paper. Three equal open-ended ground slots have been incorporated inside the ground plane in order to excite the antenna with a lower order resonant mode. On variation of the length parameter of the middle slot of the antenna, a resonant mode of lower order has been obtained near 1.52 GHz. The maximum size reduction of the designed structure is obtained, considering the lower band resonant frequency obtained is about 85.83% with a fractional bandwidth of 6.97%. The simple configuration has been fabricated on low-cost FR-4 substrate material. The proposed low-profile triple band microstrip patch obeys all the necessary standards prescribed for wireless communication and, therefore, finds its applicability in multiband wireless communication systems.

A Compact Pentagonal Ring CPW-Fed Zeroth Order Resonating Antenna with Gain Enhancement

Abstract In this work, a pentagonal ring CPW-fed zeroth order resonating (ZOR) antenna with gain enhancement is proposed. Gain enhancement is achieved by means of electromagnetic bandgap structures (EBG) loaded on patch. The proposed antenna is operated in series resonant mode, therefore resonance frequency is dominated by series parameters of the conventional CRLH transmission line. The antenna comprises of a circular patch which is imposed by interdigital capacitor and EBG structures. Meandered line inductor is connected between patch and pentagonal ground plane in order to ensure miniaturization using CRLH resonant approach. Measurement results shows that proposed antenna offers ZOR resonance at 2.7 GHz with 4.81 %, 10 dB fractional bandwidth. The antenna offers simulated gain of 1.63 dBi and 80.6 % radiation efficiency at ZOR frequency. Surface current distribution shows that how these CRLH – TL components responsible for origination of ZOR mode. Proposed antenna exhibits excellent radiation patterns with cross polarization level of −53 dB in the boresight direction.

The study of the ground plane effect on a Multiband PIFA Antenna by using Genetic Algorithm and Particle Swarm Optimization

The ground plane plays an important role on the performance of a planar inverted-F antenna (PIFA). In this regard, the ground plane modification using slots is proposed in this research to obtain a dual band antenna for WiMAX application. Â Â Â Popular optimization techniques, as genetic algorithm (GA) and particle swarm optimization (PSO), were used to design the shape of the ground plane in order to improve the bandwidth and to achieve dual band antenna instead of single band antenna. Â Â The proposed method divides the overall ground plane into different cells. Through this technique it is possible to obtain a dual band antenna reduced by more than 50%, thereby reducing the overall ground plane. Â Â Both GA and PSO designs are provided. This new method shows many advantages over PIFA antenna in terms of performance and weight.

A Novel Differential-Fed Patch Antenna on Stepped-Impedance Resonator With Enhanced Bandwidth Under Dual-Resonance

A novel design concept to enhance the bandwidth of a differential-fed patch antenna using the dual-resonant radiation of a stepped-impedance resonator (SIR) is proposed. The SIR is composed of two distinctive portions: the radiating patch and a pair of open stubs. Initially, based on the transmission line model, the first and second odd-order radiative resonant modes, i.e., TM10 and TM30, of this SIR-typed patch antenna are extensively investigated. It is demonstrated that the frequency ratio between the dual-resonant modes can be fully controlled by the electrical length and the impedance ratios between the open stub and radiating patch. After that, the SIR-typed patch antenna is reshaped with stepped ground plane in order to increase the impedance ratio as highly required for wideband radiation. With this arrangement, these two radiative modes are merged with each other, resulting in a wide impedance bandwidth with a stable radiation pattern under dual-resonant radiation. Finally, the proposed antenna is designed, fabricated, and measured. It is verified in experiment that the impedance bandwidth ( $\vert S_{\mathrm{ dd11}}\vert dB) of the proposed antenna has gained tremendous increment up to 10% (0.85–0.94 GHz) with two attenuation poles. Most importantly, the antenna has achieved a stable gain varying from 7.4 to 8.5 dB within the whole operating band, while keeping low-cross polarization.

A New Triple Band Microstrip Fractal Antenna for C-band and S-band Applications

Recently research show that some parameters such as the shapes of antenna patch and the ground plane when geometrically altered produces changes in the current density distribution of the planar structure and consequently in the resonant modes. This paper presents a new microstrip fractal antenna using the technique of inserting slots of shape fractal in ground plane in order to increase the bandwidth and insertion discontinuities in the feed line to reach specific behaviors in three resonant modes. The FR-4 substrate with dimensions 85.0 x 85.0 x 1.57 mm3 is used. Also, it used different techniques of impedance matching in feed line of antenna with changes of the width of the transmission line in order to obtain a variation in the current distribution and consequently of the impedance bandwidth for S11 ≤ -10dB for C-band (3.625 GHz – 4.2 GHz) and S-band (2.0 GHz – 4.0 GHz). Good agreement between measured and simulated results is achieved. Proposed fractal microstrip antenna can be easily designed, built and applied in wireless communication.

MODIFIED UNIDIRECTIONAL CIRCULAR PATCH ANTENNA WITH PARABOLIC SHAPE GROUND PLANE HAVING T-SLOTS FOR MICROWAVE LINKS

A modified design technique of unidirectional circular patch antenna with parabolic shape ground plane for the application of microwave links is being presented here. Firstly, T-slots are inserted diagonally at the corners of parabolic ground plane in order to increase the directivity. Thereafter, for the further improvement in the directivity as well as gain the ellipse slot in circular patch has also been introduced. The microstrip feed line is given for the proposed unidirectional antenna. The simulation analysis of the antenna is done on software CST Microwave Studio using FR-4 substrate with dielectric constant 4.3. The simulated results and parametric analysis show a good return loss with respect to -10 dB. The radiation pattern characteristic, gain characteristic, VSWR pattern and surface current distribution performance of the antenna have also been compared at different resonate frequencies.

MEMS patch antenna array with broadband and high-gain on double-layer silicon wafers

A MEMS patch antenna which can be integrated with RF module easily was designed to improve the bandwidth and gain of the traditional microstrip antenna. The equivalent dielectric constant of substrate of the microstrip antenna was optimized to greatly increase the bandwidth of the antenna by a high resistivity silicon being bonded to a low resistivity silicon to form a double-layer silicon substrate under the MEMS technology. Defected ground structure was also used on ground plane in order to restrain the harmonic radiation of antenna. Based on the above aspects, a 22 antenna array was designed with a center frequency of 10 GHz. The simulation results show that the antenna array has an impendence bandwidth of 15.9% and a gain of 10.9 dB, significantly better than traditional antennas and meets the anti-interference requirements of antennas in the fuze.

DESIGN OF ULTRAWIDEBAND MONOPOLE ANTENNA WITH MINIMUM GROUND PLANE EFFECT

A Planar ultra wideband antenna design is analyzed for increased impedance matching in the Ultrawideband (UWB) range (3.1GHz to 10.6GHz). Also the effect of the ground plane is minimized by cutting slot on the ground plane. Impedance matching of Ultrawideband (UWB) antenna can be improved by introducing simple microstrip transitions between the 50-ohm feed line and the printed disc. In this paper a dual step feed is proposed between the feed line and radiator. It also offers a very simple geometry suitable for low cost fabrication and straightforward printed circuit board integration. Here triangle slot is provided on the ground plane in order to reduce the ground plane effect. The radiator used here is elliptical disc.

Analysis and review on usage of broadband techniques in design of printed antennas for UWB communications

In this paper we have investigated on broadband antennas and done comprehensive study on effective utilization and usage of broadband techniques in the design of printed antennas for broadband communications. Here the microstrip line fed circular and semicircular printed monopole antennas are chosen for well understanding and various broadband techniques are applied in order to achieve ultra wideband (UWB), at the same we explained how there broadband techniques are employed in getting such a huge bandwidth. In particular we have simulated circular patch monopole antenna and then after etched some part of the radiating patch and ground plane in order to get broadband for UWB communication. While doing simulation study, a simple rectangular microstrip line is used for feeding the printed antennas. In this paper we have give extensive review on utilization of broadband techniques in the design of UWB antennas. Finally the proposed antennas are having frequency bandwidth under ?10 dB return loss is ranging from 3 to 15 GHz. These printed monopole antennas work well for the whole UWB frequency band 3.1?10.6 GHz .

Comb-Line Filter with Coupling Capacitor in Ground Plane

A comb-line filter with a coupling capacitor in the ground plane is proposed. The filter consists of two quarter-wavelength microstrip resonators. A coupling capacitor is inserted into the ground plane in order to build strong coupling locally along the resonators. The filtering characteristics are investigated through numerical simulations as well as experiments. Filtering characteristics that have attenuation poles at both sides of the passband are obtained. The input susceptances of even and odd modes and coupling coefficients are discussed. The filters using stepped impedance resonators (SIRs) are also discussed, and the effects of the coupling capacitor for an SIR structure are shown.

Out-of-phase Wilkinson power divider

A 1×2 Wilkinson power divider with 180° phase difference between two outputs is presented. A slotline T-junction is employed in order to split an input signal into two outputs with the same amplitude and opposite phase relationship. A 25 Ω resistor is placed between two microstrip output sides and a ground plane in order to achieve a good match and complete isolation.

Couplings control in a compact microstrip dual‐mode resonator

AbstractA compact microstrip dual‐mode resonator with slots in the ground plane is presented in this paper. Several methods for coupling between the dual modes are investigated. One of the methods involves using slots in the ground plane in order to enhance the external coupling and to introduce the necessary perturbation to the initially symmetrical structure. The proposed device requires a surface area about 6 times smaller than the area needed for a conventional patch dual‐mode resonator. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2290–2295, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22722

Simplified calculation of ground losses in low- and medium-frequency antenna systems

Calculations of ground losses are paramount in obtaining the best performance of a monopole antenna in the low- (LF) and medium-frequency (MF) bands. Ground losses are usually computed numerically, due to difficulties in the mathematical formalism. The novel approach here permits obtaining simple analytical expressions for ground-loss calculations that can be useful for determining the behavior of the ground plane. As a first approximation, the monopole antenna is placed on a perfect electrically conducting (PEC) ground plane in order to obtain the antenna current distribution and the near magnetic field, taking into account the non-zero-radius effect of the monopole. Next, the near magnetic field is used to determine the surface-current density on the ground plane below the antenna. This is divided into two zones: (1) the artificial ground plane, where either a radial-wire ground screen or a metallic layer is used to increase the soil's conductivity; and (2) the natural ground plane or bare soil up to a circular boundary a half wavelength from the antenna's base. The power dissipation is calculated from the artificial and natural ground-plane surface-current densities, and the ground-plane loss resistance is obtained. Also, an effective conductivity is defined as a measure of the ground plane's effectiveness, and the cases of quarter-wave monopoles and short top-loaded antennas are analyzed. Some results are validated by means of numerical computations and moment method simulations

Demonstration of an electrostatic-shielded cantilever

The fabrication and performances of cantilevered probes with reduced parasitic capacitance starting from a commercial Si3N4 cantilever chip is presented. Nanomachining and metal deposition induced by focused ion beam techniques were employed in order to modify the original insulating pyramidal tip and insert a conducting metallic tip. Two parallel metallic electrodes deposited on the original cantilever arms are employed for tip biasing and as ground plane in order to minimize the electrostatic force due to the capacitive interaction between cantilever and sample surface. Excitation spectra and force-to-distance characterization are shown with different electrode configurations. Applications of this scheme in electrostatic force microscopy, Kelvin probe microscopy and local anodic oxidation is discussed.

Artificial magnetic conductor using split ring resonators and its applications to antennas

AbstractAn artificial magnetic conductor using the split‐ring resonators (SRRs) printed on conductor‐backed dielectric substrate is presented. The simulation and measurement verify that the magnetic conductor is successfully accomplished around the resonant frequency. As an antenna application, the characteristics of a horizontal wire antenna placed above the SRR array, as well as a conducting ground plane and a grounded dielectric slab, are investigated and compared. A maximum gain of 4.34 dBi is obtained for the wire antenna above the SRR array. The results confirm that the split resonators can successfully be used to replace the antenna ground plane in order to improve their performance. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 329–334, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21341