Omnidirectional microstrip patch antenna with reconfigurable pattern and polarisation. Rectangular microstrip antenna fringing fields have a great effect on the performance of a microstrip antenna. The basics of patch antennas, updated orban microwave. I want to know how to measure e field, h field and gain of microstrip antenna. The radiation pattern of microstrip or patch antenna is. The radiation is due to the fringing field between the periphery of the patch and the ground plane. Analysts finite element wave ports are used to drive the antenna and radiation patterns and. Generally, hemispherical coverage is provided by a patch antenna at an angle of 30. This is accomplished by properly choosing the mode field configuration of excitation beneath the patch. The patch without the feeding network was simulated in ansoft hfss to adjust w for resonance at 2. The patch may be in a variety of shapes, but rectangular and circular are the most common. In this work, the patter of two designs of a microstrip patch antenna have been analyzed and studied.
A patch antenna is a narrowband, widebeam antenna fabricated by etching the antenna element pattern in metal trace bonded to an insulating dielectric substrate, such as a printed circuit board, with a continuous metal layer bonded to the opposite side of the substrate which forms a ground plane. The length l was chosen to be the same as w to obtain a symmetric radiation pattern. Most often, microstrip antennas are made by etching the patch from a printed. Antenna theory radiation pattern radiation is the term used to represent the emission or reception of wave front at the antenna, specifying its strength. In microstrip antennas the electric filed in the center of the patch is zero. Endfire radiation can also be accomplished by judicious mode selection. Because of the presence of the fringing field between the patch edges and ground plane, microstrip patch antennas primarily radiate. The fringing field created on patch antenna depends on the dielectric constant of patch element.
What is process for measurement e, h field radiation pattern and gain of patch antenna in anechoic chamber. I selected indbefar expression to see the far field gain pattern in db. Microstrip, patch, antenna, slit directivity of the antenna, electric far field. The typical radiation pattern of a rectangular microstrip antenna is shown in. Nearfield antennas, which utilize strong magnetic fields in the region near an antenna, are becoming increasingly popular even though the range of nearfield communication is limited to a few wavelengths. Because the effective length of the microstrip conductor is a halfwavelength, the electric field is at maximum at the left and right edges due to the effective open circuit and the repeating field pattern at halfwavelength intervals.
For good antenna performance, a thick dielectric substrate having a low dielectric constant microstrip antenna to receive fm radio at 100 mhz it would be on the order of 1 meter long which is a very large circuit for any type of substrate. In this video, i have explained microstrip antenna or patch antenna by following outlines. Selecting best feeding technique of a rectangular patch. Generally, patch antenna has a shape of rectangle, and it can be feed with copper cable or microstrip line in our case.
Microstrip antenna an overview sciencedirect topics. Figure 2 present the simulated 2d cut view and 3d far zone eplane radiation patterns for this antenna. What is fringing effect in microstrip patch antenna. This is in agreement with the theoretical radiation pattern for these structures. The patch of the antenna must be a very thin conductive region, t microstrip antennas. The formulation of the radiation problems is based on the combined field integral equations. The following image shows a microstrip or patch antenna. It consists of a conventional microstrip patch of triangular shape and an array of patches with pentagons shapes that are arranged in front of the main patch. A microstrip patch antenna comprises of a patch element, which is a radiating material on one side of a dielectric substrate and a ground plane on the other side of it.
The amplitude and phase maps of three orthogonal electric field components. Coax fed patch antenna with waveport at different location this example demonstrates the use of a coaxial probefed rectangular microstrip patch antenna. Measurement of a circularly polarized patch antenna at 1. Pattern analysis of the rectangular microstrip patch antenna. The size of a microstrip antenna is inversely proportional to its frequency. Hence a compromise must be reached between antenna dimensions and antenna performance. A microstrip patch antenna mpa consists of a conducting patch of any planar or nonplanar geometry on one side of a dielectric substrate with a ground plane on other side.
At xband a microstrip antenna is on the order of 1 centimeter long easy to realize on softboard technology. The fringing fields around the antenna can help explain why the microstrip antenna radiates. These results show that a microstrip patch antenna mainly radiates in the vertical direction. Electrooptic mapping and finiteelement modeling of the. Electric field distribution of rectangular microstrip antenna. When the antenna is excited, the waves generated within the dielectric undergo reflections and the energyis radiated from the edges of the metal patch,which is very low. It basically consists of two metallic plates separated by a dielectric layer.
This is simply a form of circular polarization in which the electric field in one direction is not strictly equal to the electric field in the perpendicular direction 6. The fields of the microstrip antenna are plotted in figure 2 for wl0. The transmissionline model of the rectangular microstrip antenna utilizes an equivalent radiating slot of width w, and height h, to represent each of the radiating edges fig. Thus the element and feed line, and usually other elements, power dividers, etc.
Consider the side view of a patch antenna, shown in figure below. It also has a wide angle of beam in its radiation pattern. This unit will give the basic picture regarding microstrip antenna configurations, methods of analysis and some feeding techniques. Note that since the current at the end of the patch is zero open circuit end, the c. 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. At frequencies lower than microwave, microstrip patches dont make sense because of the sizes required. For am radio at khz, the microstrip patch would be the size of a football field. Tm stands for a magnetic field distribution between patch and ground that is transverse to the zaxis of the antenna shown in figure 1. The directivity of patch antennas is approximately 57 db.
A microstrip or patch antenna is a lowprofile antenna that has a number of. Siddiqui1, sheikh sharif iqbal2 1institute of radio physics and electronics, university. In order for the antenna to operate under the fundamental tm10 mode, the length of the patchmust be slightly less than. Analysis and design of the rectangular microstrip patch antennas. I examine the microstrip patch antenna example in the application libraries. Some of the pulse will radiate away, and some of the power will be reflected back down the microstrip line. Pdf radiation pattern investigation of n element microstrip patch. The patchmicrostrip object is a microstrip patch antenna. Basically, a microstrip patch antenna is composed of a trace of copper or any other metal of any geometry on one side of a standard printed circuit board. How to synthesize the radiation pattern of an antenna. The patch of the antenna must be a very thin conductive region, t microstrip antenna. There is another bottom layer underneath blue area covering the whole area that is the ground. The amplitude and phase maps of three orthogonal electricfield components, measured using electrooptic crystals above the patch, also have revealed the transition from the near field to the far field of the radiation pattern. The patch is generally made up of a conducting material such as copper or gold and can take any possible shape like rectangular, circular, triangular, elliptical or some other common shape.
The most widely used printedcircuit antenna is the microstrip patch, which in its simplest form is a rectangular or circular patch of metal fed by the microstrip upper conductor. Design and radiation characterization of rectangular microstrip. Microstrip patch antennae radiate primarily because of the fringing fields between the patch edge and the ground plane. The metallic plates are usually made of copper or some other highly conductive material. To determine the width w, the microstrip patch antenna calculator was used to provide an initial starting point. In this case, each vector starts at the origin and lies along the specified points on the x, y, and zaxes. In the drawing above, blue area is the substrate and brown area represents the top conducting layer which is half of the antenna.
Advantage of adding small patches is better radiative properties such as high gain and radiation efficiency. In case of satellite communication circularly polarized radiation patterns are required and this can be realized using either square or circular patch with one or two feed points. Fig 3 microstrip patch antenna in order to operate in tne fundamental mode,length of the patch should be slightly less than. The microstrip patch is designed so its pattern maximum is normal to the patch broadside radiator. In this numerical experiment, a short pulse will be launched from the end of a microstrip, which will travel towards the patch antenna. Simulate and analyze a rectangular patch antenna using ansys hfss, including return loss and 3d radiation fields. This rectangular microstrip patch antenna is designed for wireless communication application that works at 2. M icrostrip p atch a ntenna microstrip patch antenna consists of a radiating patch. A microstrip patch antenna or simply a patch antenna is a very common antenna type used in cell phones and many other electronic devices. The results obtain that microstrip patch antenna can be used as client antenna in computer and workable antenna for wireless fidelity.
Normalized radiation pattern for microstrip patch antenna. A compact microstrip patch antenna is designed for use in a cellular phone at 1. The microstrip patch antenna is represented by two slots. Microstrip patch antenna meets all requirements and various types of microstrip antennas have been designed for use in mobile communication systems. I just want to see the radiation pattern of the antenna. Microstrip patch antennas are usually used for wireless. Microstrip patch antenna have been analyzed and studied. It is a popular printed resonant antenna for narrowband microwave wireless links that require semihemispherical coverage. Rectaangular microstrip patch antenna for wireless. This transverse with respect to the zaxis is usually dropped because the magnetic fields in patch antennas are always transverse to their zaxis. Electrooptic mapping and finiteelement modeling of the near field pattern of a microstrip patch antenna abstract. The fields are linearly polarized, and in the horizontal direction when viewing the microstrip antenna as in figure 1a well see why in the next section. It usually consists of a metal patch on top of a grounded dielectric substrate. The figure below represents the radiation pattern of the microstrip antenna.