Conventional single element microstrip patch antennas have a low directivity 67dbi 1. The basics of patch antennas, updated orban microwave. The subject of directivity enhancement of microstrip patch antennas mpas, using either a frequency selective surface fss or a doublenegative dng metamaterial slab, has been investigated by. Enhancement of gain and directivity for microstrip antenna using. Introduction an microstrip antenna msa 1 in its simplest form consists of a radiating patch on one side of a dielectric substrate and a ground plane on the other side.
Index termsdirectivity, metamaterial, microstrip patch an. To study the theory of microstrip transmission line we have two different cases. The scattering parameters are utilized to plan and corroborate the dng structure. Us20050285795a1 broadside highdirectivity microstrip patch. High directivity of microstrip patch antenna using metamaterial muhammad waqas1, shahid bashir2, muhammad junaid. The directivity of a patch can be estimated quite easily. The gain of the antenna is closely related to the directivity, but takes into consideration the losses in the antenna as well as its directional capabilities. Enhancement of directivity of rectangular microstrip. To have a greater directivity, an array can be formed by using these patch antennas. Antenna gain antenna gain is defined as antenna directivity times a factor representing the radiation efficiency. In the second part of this antenna basics series, you will learn more about the physics of how antennas work.
A classical patch, such as a square shaped patch, presents a single lobed broadside pattern in its fundamental mode tm10 or tm01 with a low directivity. One familiar application of this type of patch antenna is the rectangular antenna usually in a plastic housing used widely in 2. Without changing the original microstrip patch antenna size, the use of metamaterials made it possible to nearly double antenna directivity. Comparative study between microstrip patch and patch array antenna has been undergone. Microstrip patch antennas or simply patch antenna are increasingly useful because the antenna is printed directly onto a circuit board. A single highdirectivity microstrip patch antenna mpa having a rectangular profile, which can substitute a linear array is proposed. Results and discussion several parameters like gain, directivity, radiation efficiency and return losses of antenna with transmission line are simulated and compared between conventional mpa and dng based mpa is discussed below.
Directivity enhancement of microstrip antenna loaded with fss. For a square patch antenna fed in the manner above, the input impedance will be on. High directivity microstrip antennas comprising a driven patch and at least one parasitic element placed on the same plane, operate at a frequency larger than the fundamental mode of the driven patch in order to obtain a resonant frequency with a high directivity broadside radiation pattern. Pdf high directivity of microstrip patch antenna using. Introduction in its most basic form, a microstrip patch antenna consists of a radiating patch on oneside of a dielectric substrate which has a ground plane on the other side for good antenna performance, a thick dielectric substrate having a low dielectric constant isdesirable since this provides better efficiency, larger bandwidth and better. In this paper, we consider the problem of enhancing the directivity of an aperture coupled microstrip patch antenna. Microstrip antennae are very simple in construction using a conventional microstrip fabrication technique. The main objective of this project is to develop the antenna that has high gain, directivity, wide bandwidth and higher efficiency. A patch antenna radiates power in certain directions and we say that the antenna has directivity usually expressed in dbi. Abstract in this paper the directivity of microstrip patch antenna is enhanced by using. Design and implementation of patch antenna 8 figure 2.
Microstrip antennas can be designed as very thin planar printed antennas and they are very useful elements for communication applications 4. Pdf the rectangular microstrip patch antenna is explored from. Enhancement of directivity of rectangular microstrip antenna using. The study of microstrip patch antennas has made great progress in recent years. In electromagnetics, an antennas power gain or simply gain is a key performance number which combines the antennas directivity and electrical efficiency. In this article, we present the results of a comparative study of three different types of superstrates used to enhance the directivity of a microstrip patch antenna. Here you can download the free lecture notes of antenna and wave propagation notes pdf awp notes pdf materials with multiple file links to download. Directivity enhancement of microstrip antenna loaded with. Their low profile design, often square or rectangular, allows them to be mounted to flat surfaces.
Keywords rectangular patch antenna, polypropylene substrate. It was invented to allow convenient integration of an antenna and other driving circuitry of a communication system on a common printedcircuit board or a semiconductor chip carver and mink, 1981. Fig 1 basic structure of microstrip patch antenna so many advantages and applications can be mentioned for microstrip patch antennas over conventional antennas. The antenna was analyzed via computer simulations and experimental measurements. To have a greater directivity, an array can be formed. Genetic algorithm optimization of a highdirectivity. The gain of these antennas is between the ranges between 8dbi to 20dbi. Enhancement of gain and directivity for microstrip antenna.
Full writeup for 3rd edition is given directivity of microstrip patches including finite ground planes. It has low radiation power and narrow frequency bandwidth. Often microstrip antennas are also referred to as patch antennas. The return loss, radiation pattern and directivity are studied using hfss software. Antenna and wave propagation pdf notes book starts with the topics covering antenna basics, thin linear wire antennas, antenna arrays. The patchmicrostrip object is a microstrip patch antenna. Patch antenna array in order to increase main beam gain, reduce side lobe radiation, and increase directivity, the patch antenna design was expanded to a four element array. Additional benefits of patch antennas is that they are easily fabricated making them cost effective. We will discuss later in this work more parameters of the antenna in connection with microstrip patch antenna like radiation pattern, efficiency, quality factor, directivity, gain, and more. Hence the directivity of microstrip antenna msa is increased by slightly increasing the dimensions of patch antenna and multilayer structure with covered dielectric 5. Dec 04, 2012 introduction in its most basic form, a microstrip patch antenna consists of a radiating patch on oneside of a dielectric substrate which has a ground plane on the other side for good antenna performance, a thick dielectric substrate having a low dielectric constant isdesirable since this provides better efficiency, larger bandwidth and better. Easy to use in an array to increase the directivity. Considering as an example a microstrip antenna operating within the umts band, the broadside gain of the antenna was improved by 3. A brief tutorial on microstrip antennas part 2 microwaves.
The radiation pattern of a microstrip or patch antenna is shown above. It is a measure of how directional an antenna s radiation pattern is. High directivity of microstrip patch antenna using. An original method is outlined to guarantee matching for each. The advantage of an antenna having a broadside radiation pattern with a larger directivity than that of the fundamental mode, is that with one single element it is possible to obtain the same directivity as an array of microstrip antennas operating at the fundamental mode, the fundamental mode being the mode that presents the lowest resonant frequency, but there is no need to employ a feeding. Directional patch antenna array design for desktop. Microstrip patch antenna directivity, antenna design. Pdf in this paper, a different double negative dng metamaterial is demonstrated to upgrade the performance of microstrip patch antenna mpa. Us20050285795a1 broadside highdirectivity microstrip. There are cases in which the term directivity is implied to refer to its maximum value.
A comparative study of directivity enhancement of microstrip. Patterns are somewhat hemispherical, with a moderate directivity about 68 db is typical. The width w of the microstrip antenna controls the input impedance. Name is the property name and value is the corresponding value. Microstrip patch antenna design santa clara university. It is promising to reduce the lateral radiation and obtain an enhanced directivity when the sng mtms are applied in the microstrip patch antenna. Keywords directivity, rectangular microstip antenna, ie3d, vswr i.
An antenna that radiates equally in all directions would have effectively zero directionality, and the directivity of this type of antenna would be 1 or 0 db. Demonstration of an xband multilayer yagilike microstrip. Nishant kumar 1, ashutosh kumar pandey 1, aditya prakash 1, shiv mani kumar 1, rupali bihari 1, manas ranjan jena 2. Design and radiation characterization of rectangular microstrip.
The directivity expressed with respect to the directivity of a dipole has db d as its unit. The above equation says that the microstrip antenna should have a length equal to one half of a wavelength within the dielectric substrate medium. Pdf antenna and wave propagation notes pdf awp notes sw. Pdf directivity enhancement of microstrip antennas using. The proposed antenna is analyzed based on transmission line analogy and reciprocity theorem. A directivity as well as bandwidthenhancement scheme, based on a verticallystacked microstrip yagilike antenna is demonstrated. Microstrip antennas have high q q 100 is common, which means that they have small bandwidths. Enhancement of directivity of rectangular microstrip antenna. If the antenna had a 100% radiation efficiency, all directivity would be converted to gain. Microstrip antenna an overview sciencedirect topics. Microstrip patch antenna consists of a radiating patch on one side of a dielectric substrate fr4 that has a ground plane cu on the other side as shown in fig. J theory and analysis of differentiallydriven microstrip antennas. As a transmitting antenna, the gain describes how well the antenna converts input power into radio waves headed in a specified direction.
The msa also should have good bandwidth and for this two patch technique called feed patch and parasitic patch are used. Highdirectivity microstrip antennas comprising a driven patch and at least one parasitic element placed on the same plane, operate at a frequency larger than the fundamental mode of the driven patch in order to obtain a resonant frequency with a highdirectivity broadside radiation pattern. The radiating elements and the feed lines are usually photo etched on the dielectric substrate. Properties not specified retain their default values. Therefore, the design of high directivity microstrip patch antennas is a challenging task. This antenna has directivity diversity and is based on a fourelement array. In this paper, a different double negative dng metamaterial is demonstrated to upgrade the performance of microstrip patch antenna mpa.
Em analysis of a microstrip patch antenna mpa loaded with frequency selective surface fss based superstrate is presented in this paper for directivity enhancement. For efficacy of the approach, the radiation characteristic of a rectangular mpa is validated with that of reported. Simulated as well as measured results show that this structure allows for high bandwidth. The sloper antenna is a slanted vertical dipole antenna attached to the top of a single tower. Also the antenna characteristics such as efficiency, directivity, gain and resonant frequency parameters are measured. The antenna efficiency is the ratio of directivity to gain. The bandgap properties of the material suppressed surface waves and reduced antenna backward wave loss. The radiation pattern of microstrip or patch antenna is broad. A single high directivity microstrip patch antenna mpa having a rectangular profile, which can substitute a linear array is proposed.
Improving microstrip patch antenna directivity using ebg. Therefore, the design of highdirectivity microstrip patch antennas is a challenging task. The directivity or gain of an antenna is defined as the ratio of the maximum value of the power radiated per unit solid angle to the average power radiated per unit solid angle. Rectangular microstrip antenna a, and its side view b because of the fringing effects, electrically the patch of the microstrip antenna looks greater than its physical dimensions. As you can see from the above table, the directivity of an antenna can vary over several order of magnitude. Simulation of rectangular microstrip antenna by integrating matlab in visual basic diyala journal of engineering sciences, vol. You can specify several namevalue pair arguments in any order as name1, value1. The microstrip antenna is a relatively modern invention. In this case, each vector starts at the origin and lies along the specified points on the x, y, and zaxes. Alternate feed methods a common variation in patch antenna design is the location and routing of the feed, to obtain a desired feedpoint impedance, to. Threeelement vectors of cartesian coordinates in meters. The fundamentals of patch antenna design and performance.
It is designed by using genetic algorithms with the advantage of not requiring a feeding network. The driven patch, the parasitic elements and the gaps between them may be shaped as multilevel andor. Design and analysis of microstrip patch antenna arrays. Patch antenna array in use for wifi communications refer to appendix a for the single patch antenna design procedure. The directivity of a microstrip patch can be found from the cavity models of patches and integrated over the hemisphere to compute directivity. Pdf high directivity of microstrip patch antenna using metamaterial. Hence, it is important to understand directivity in choosing the best antenna for your specific application. The antenna covering layers were formed from zerorefractive materials to optimize antenna directivity. The g5rv antenna is a dipole antenna fed indirectly, through a carefully chosen length of 300. Section ii explains the design procedure of an aperture coupled microstrip patch antenna acmpa covered by ebg structure and section iii is about the simulation results. To achieve the dualfrequency antenna, the conventional patch antenna is excited along the diagonal. Us8026853b2 broadside highdirectivity microstrip patch. Pdf a directivitydiversity microstrip antenna array in.
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