dimensions and thickness on the electrical performance of the patch antenna. In this paper, gain, return loss and bandwidth which are of importance for Directivity of an antenna defined as “the ratio of the radiation intensity in a given. Rectangular microstrip antenna with fractal over the patch is considered with studio, fractals, radiation pattern, voltage standing wave ratio. I. INTRODUCTION play an important role to enhance the bandwidth and make it more slim and. of a rectangular patch antenna on the thick PTFE substrate. (0 –0 ). The above anisotropy relation has been obtained in the lit- erature for the.
Effect of Substrate Thickness Variation 6. Introduction Microstrip patch antennas consist of a metallic patch on a grounded substrate. Microstrip antennas have found widespread applications for microwave as well as millimeter wave systems [ 2 ]. Compatible devices are widely used in our daily lives such as mobile phones, laptops with wireless connection, wireless universal serial bus USB dongles etc and microstrip patch antenna plays a very significant role for the miniaturization of these devices [ 3 ].
The applications in present-day mobile communication systems usually require smaller antenna size in order to meet the miniaturization requirements of mobile units.
Thus, size reduction and bandwidth enhancement are becoming major design considerations for practical applications of microstrip antennas. The microstrip patch antennas are well known for their performance and their robust design, fabrication and their extent usage. The inherently narrow impedance bandwidth is the major weakness of a microstrip antenna [ 4 ]. Although we used rectangular shaped patch but the radiating patch can be of any geometrical configuration like square, rectangle, circular, elliptical, triangular, E-shaped, H-shaped, L-shaped, U shaped etc.
The material which has the dielectric constant in the range of 2. When we change the substrate material and the thickness of substrate of a microstrip antenna, it changes the system performance. Therefore, in order to introduce appropriate correctness in the design of the antenna, it is important to know the effect of changing dielectric substrate material and substrate thickness. A set of simulation and measurements of inset feed rectangular patch antenna on different substrate material RT DuroidGMLRO and FR-4 and on the same substrate material by varying substrate thickness is presented in this research paper.
The design, simulation and measurements are performed by advanced design system ADS momentum. Inset feed rectangular microstrip patch antenna layout. Feeding Technique A feedline is used to excite the antenna for making radiation by direct or indirect contact. Microstrip patch antennas can be fed by a variety of methods. This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
The electrical characteristics of the embedded structure are evaluated using MoM simulations. The manufactured prototypes are characterized in terms of return loss, gain, and radiation pattern measurements in an anechoic chamber. Introduction Microstrip patch antennas offer an attractive solution to compact and ease-low-cost design of modern wireless communication systems due to their many advantages as light weight and low volume, low profile, planar configuration which can be easily made conformal to host surface, low fabrication cost, and the capability of obtaining dual and triple frequency operations.
When mounted on rigid surfaces microstrip patch antennas are mechanically robust and can be easily integrated with microwave integrated circuits MICs. However, microstrip patch antennas suffer from a number of disadvantages as compared to conventional nonprinted antennas. Some of their major drawbacks are the narrow bandwidth, low gain, and surface wave excitation that reduce radiation efficiency.
To overcome one of their more critical restrictions, narrow bandwidth, several techniques can be used [ 1 ]. First of all, a thicker substrate with a low dielectric constant or a ferrite composition provides a wider bandwidth but the first approach leads to no low-profile designs and increased in size, whereas the second solution is expensive. Another possibility is multiresonator stack configuration with the inconvenient of resulting large thickness prototype [ 23 ].
The surface waves can be minimized using electromagnetic band-gap structures whereas for obtaining a high gain antenna an array configuration for the patch elements is needed. The research in the field of electromagnetic band-gap structures has become attractive in the antenna community and is considered to be a key technology for improving microstrip patch antenna performances [ 4 — 6 ].
The use of metamaterials, such as the frequency selective surfaces FSS [ 7 — 9 ] is an alternative to face antennas and microwave circuit problems and can provide either EBG or AMC behavior. Depending on the intended application, the 2.
Microstrip Patch Antenna Bandwidth Enhancement Using AMC/EBG Structures
In this paper, the main goal is to improve the bandwidth and the radiation properties of a microstrip patch antenna in the 2.
The aim of this work is challenging because two resonant structures are involved and when integrated together their resonant behavior is mutually influenced. Firstly, the design of a microstrip patch antenna, henceforth referred as patch antenna, is shown followed by an adaptation of an AMC design recently presented by the authors to operate at 2. Then, the patch antenna is placed above the AMC. This combination will be henceforth referred as Patch antenna-AMC.
Secondly, the AMC structure is modified to act as an EBG at a frequency close to the patch antenna resonance frequency. Finally the EBG is combined with the patch antenna on the same layer, resulting in a design with a uniplanar feature and reduced cost. This combination will be henceforth referred as patch antenna-EBG. Return loss, gain, and radiation patterns of the three prototypes all having the same dimensions are analyzed based on measurements in an anechoic chamber.
Microstrip Antenna Design The microstrip patch antenna is a narrow band design.
Theoretical maximum gain and bandwidth of an antenna
In this work, the patch antenna suitable for RFID applications at 2. The geometry of the patch antenna with its dimensions is shown in Figure 1 a.
The antenna design has been carried out by a set of method-of-moments MoM simulations with commercial software [ 19 ]. From Figure 4it can be extracted that the simulated operating bandwidth of the patch antenna is 20 MHz. AMC Characterization An adaptation of the AMC previously designed by the authors [ 20 ] is carried out shifting the resonant frequency to 2.
Based on the Bloch-Floquet theory and on the finite element method FEMa single cell of the lattice with periodic boundary conditions PBCs on its four sides is simulated in order to obtain the frequency band where the periodic structure acts as an AMC.
Theoretical maximum gain and bandwidth of an antenna
The phase of the reflection coefficient on the AMC surface is computed using a uniform incident plane wave see Figure 2 a.
The unit cell dimensions are mm2 and its geometry exhibits four symmetry planes. The simulated reflection phase of normally incident plane wave on the AMC surface versus frequency is represented in Figure 2. The AMC resonant frequency is 2. The structure exhibits several advantages such as uniplanar feature since neither multilayer substrate no via holes are required, simplifying the implementation and reducing its costs.
A suspended strip line over the cell arrangement is used to test the transmission response of the electromagnetic waves. The strip height is 0. The structure will block the transmission of power along the strip line for frequencies within the band gap region and a noticeable reduction in can be observed at a certain frequency band.
The band-gap of the EBG lattice is designed to be adjacent to the frequency band of the patch antenna, so that when integrating the two structures on the same layer, their resonances couple each other, and, as a result, a wider bandwidth will be generated without disturbing other characteristics of the patch antenna such as the radiation pattern. The dimension of the unit cell in the case of EBG characterization is mm.