This radiation pattern shows that the antenna radiates more power in a certain direction than another direction. Fundamental specifications of patch antennas radiation pattern the patchs radiation at the fringing fields results in a certain far field radiation pattern. Request pdf improving radiationpattern distortion of a patch antenna having a finite ground plane this paper presents a very useful and yet simple method. Its not feasible to center the antenna in the devices i worked on, so wed kind of shove the antenna in the corner of the pcb. Radiation patterns of the circular patch with finite ground plane size are computed. The distance between the patch and the ground plane the substrate or. The length of the patch the shape of the patch the ground plane cutting off radiation behind the antenna this picture shows a typical radiation pattern for a square patch antenna. Measurement of a circularly polarized patch antenna at 1. The ideal pattern is roughly hemispherical in nature. The larger the groundplane, the higher the antenna gain in general. Microstrip patch antenna array with cosecantsquared.
The radiation pattern of the antenna is shown in figure 2 while figure 3 shows the radiation pattern of the antenna with slot in the ground plane. Passive patch antenna application note ground plane effect on gain for apae series patch antenna is a passive component and therefore, its gain is defined as antenna directivity times the radiation efficiency. To illustrate how this may help, two instances will be illustrated, the quarterwavelength patch antenna, which leads into the planar invertedf antenna pifa. The thickness of the ground plane or of the microstrip is not critically important. Photoetching is done to fabricate the radiating element and feed lines on the substrate. The bottom of patch is filled with ground but the layer adjacent to the ground filled layer is a power plane. The antennas feed is a through hole and reaches the bottom of board, where it meets a 50 ohm transmission line. This would result in a destructive phase contribution, typically affecting the radiation pattern and the vswr tuning of the antenna.
The proposed configuration of the antenna is shown in figure 1. Most radiation analyses of microstrip antenna are based on the assumption of an infinite ground plane. The dielectric material is mounted on a ground plane, where the ground plane supports the whole structure. The proposed antenna shows a stable radiation pattern at lower frequency order 4. The position of the patch on top of the ground plane has effects on the radiation properties of the antenna similar to a variation of the size l. A metal patch mounted at a ground level with a dielectric material inbetween constitutes a micro strip or patch antenna. Analysis of the effects of rectangular ground plane on. A microstrip patch antenna is comprised of a radiating metallic patch situated on one side of a nonconducting substrate panel with a metallic ground plane placed on the other side of the panel. Patch antenna ground plane electrical engineering stack. The simulation results show that the gain of a circular patch antenna varies with the ground plane size. An antenna that is formed by etching out a patch of conductive material on a dielectric surface is known as a patch antenna. H plane represents the horizontal pattern, whereas v plane represents the vertical pattern.
Whats the difference between a dipole and a ground plane. Radiation pattern there are many design choices which change how a radiation pattern appears. Typical gain and axial ratio of a patch antenna with respect to square ground plane size. Another variant of patch antenna with the partially etched ground plane, also known as printed monopole antenna, is a very versatile antenna for dualband operations. Radiation patterns of the circular patch with finite ground plane size are computed and compared with the experimental data, and the agreement is found to be good.
The basics of patch antennas, updated orban microwave. The directivity of patch antennas is approximately 57 db. For example, some patch antennas are approximately half a wavelength on each side. The following image shows a microstrip or patch antenna. Assuming all radiation occurs in one ha lf of the hemisphere, this results in a 3 db directivity. As predicted, the radiation pattern for the microstrip patch antenna is directional in pattern. Figure 4 shows a typical radiation pattern for a square, half wave patch. The radiation pattern of microstrip or patch antenna is.
The influence of finite substrate and ground plane size on the radiation pattern performance of lprobe feed thick patch antennainpackage array in lowtemperature cofired ceramic ltcc for 60ghz wireless communications is investigated and compared when the antenna array is with and without the soft surface structure, which is used to reduce surface. Estimating a large phased array antenna radiation pattern by computer electromagnetic simulation. Patch antenna ground plane effect on radiation pattern higgler electrical 2 aug 16. Mackenzie langley research center, hampton,virginia. Initially, a circular patch with a finite ground plane is studied. Em modeling of farfield radiation patterns for antennas. In this antenna, one corner of the patch or sometimes one edge is grounded with a ground pin. The fundamentals of patch antenna design and performance. Setting groundplanewidth to inf, uses the infinite ground plane technique for antenna analysis. These effects include frequency shift, gain, axial ratio and radiation pattern. Improving radiationpattern distortion of a patch antenna.
Typical radiation pattern of a 16 x 16 mm patch antenna figure 18. I currently work for a different company that makes electronics with gps patch antennas in them. The antenna efficiency is defined as the ratio of the radiated power to the input power. Patch antenna radiation properties as functions of the ground plane. Download scientific diagram patch antenna radiation properties as functions of the ground plane radius. Estimating a large phased array antenna radiation pattern.
The distance between the patch and the ground plane the substrate or dielectric height h determines the bandwidth. It confirms that the antenna has a stable and unidirectional radiation pattern. Actual environments are different, and the ground pl. William orr, radio handbook, 22 nd edition, howard w. The radiation pattern of a standard patch antenna looks similar to that shown below in figure 5. Aug 07, 2007 the patch antenna in figure 7 shows how simple these antennas can be.
Design of microstrip antenna array with suppressed back lobe. Patch antenna is a passive component and therefore, its gain is defined as antenna directivity times the radiation efficiency. Patch antenna ground plane effect on radiation pattern i used to work for a company that made electronics with gps patch antennas in them. Finally, to validate the explanation above described with. The substrate and ground plane size effect on radiation pattern of 60ghz ltcc patch antenna array lei wang 1, 3, yongxin guo 1,2, and wen wu 3 1national university of singapore, singapore 117583 2national university of singapore suzhou research institute, suzhou, jiangsu province, china, 215123 3ministerial key laboratory of jgmt, nanjing university of science and. This antenna is often built of printed circuit board material and the substrate makes up the patch antennas dielectric. Parasitic rectangular patch antenna with variable shape. This is the vertical radiation pattern of a ground plane antenna over a socalled perfect ground. Experimental and theoretical results show that the back radiation is influenced by the sidelobe level and can further be. In this paper a rectangular microstrip antenna with slots as shown on fig. I am designing a four layer board in which a patch antenna is used for a gps receiver.
A microstrip patch or array with infinite ground plane is a theoretical antenna, but patch with finite ground plane is of practical interest. The radiation patterns exhibit typical patch antenna characteristics. Patch antennas come in various shapes and sizes and consist of a patch of metal directly above a ground plane. The ground plane must have comparatively very large dimensions than the patch. The radiation characteristics of microstrip antennas consisting of two patch elements on small size substrates are studied by means of an approximate solution technique. One should read the text above to note that this text should be.
I used to work for a company that made electronics with gps patch antennas in them. Keywordscircular microstrip patch antenna antenna, cmparetur n loss, radiation pattern, antenna efficiency, radiation efficiency. The antennas radiation pattern is in the yzplane at 11. Patch antenna ground plane effect on radiation pattern. Patch and ground plane design of microstrip antennas by. The main disadvantage of these antennas is their relatively large size compared to other types of antennas.
Design and implementation of patch antenna 7 mmic designs, and when the particular patch shape and mode are selected, they are very versatile in terms of resonant frequency, polarization, pattern, and impedance. You can specify several namevalue pair arguments in any order as name1, value1. It follows a cosecantsquared curve over an angular range of 60. In this paper, a rectangular patch with the variable ground plane is proposed. This paper presents a very useful and yet simple method of improving the radiationpattern distortion of a patch antenna having a finite ground plane. A thicker substrate increases the gain to some extent, but may lead to undesired effects like surface wave excitation.
Ground plane size the larger the groundplane the higher the gain in general. This is a simple rectangular patch built over a rectangular ground plane. There is a single main lobe with a fairly wide beamwidth with shallow nulls pointing up and down from the antenna. Gain tilt will occur as the radiation pattern will adjust toward the larger surface, and conversely be reduced on the smaller surface. The patch antenna in figure 7 shows how simple these antennas can be. Influence of the ground plane structure on the radiation pattern of. The influence of finite substrate and ground plane size on the radiation pattern performance of lprobe feed thick patch antenna inpackage array in lowtemperature cofired ceramic ltcc for 60ghz wireless communications is investigated and compared when the antenna array is with and without the soft surface structure, which is used to reduce surface wave effect and improve the.
Introduction onopole antennas are half the size of their dipole. The circular micro strip patch antenna as shown in figure 1. In a monopole antenna, the radiation pattern of the monopole plus the virtual image antenna make it appear as a two element centerfed dipole antenna. The ground plane is then deformed, above and below the substrate, to increase the gain or shape the radiation patterns. Name is the property name and value is the corresponding value. The ground plane has substantial effects on the performance of the antenna. In recent years, the current trend in commercial and government communication systems has been to develop low cost, minimal weight, low. Properties not specified retain their default values. Limited ground effect on the radiation pattern of microstrip antenna is already known. But, if the size of the ground plane is greater than the patch dimensions by approximately six times. A simple method to predict e plane radiation, except in the neighbourhood of the. Also the centre frequency of the antenna will changes in size of the groundplane. This is because an infinite pec groundplane was not used in the simulation to be more. The radiation pattern in the yzplane is slightly tilted and some radiation occurs below groundplane.
These are very low size antennas having low radiation. A lowprofile antenna over a ground plane that radiates a directive lobe in the end fire direction is described in this paper. Effect of changes in basic parameter microstrip patch antenna on its radiation patter and other parameters can be determined by using gui. Improving radiationpattern distortion of a patch antenna having a. The patch is of length l, width w, and sitting on top of a substrate some dielectric circuit board of thickness h with permittivity. By default, ground plane width is measured along yaxis. I understand that a patch antenna has a radiation pattern similar to the following picture from wikipedia when the patch antenna is centered over the ground plane. Jul 16, 20 this is the vertical radiation pattern of a ground plane antenna over a socalled perfect ground. In a patch antenna, most of the propagation is above the ground plane and can have high directional gain. An array of 16 wire patch antenna wpa fed by an integrated 16 ways power divider has been designed. Here the previously designed 8 element array with corporate feed, as shown in figure 6. The substrate and ground plane size effect on radiation. A simple method to predict e plane radiation, except in the neighbourhood of the geometrical optical boundary.
Ground plane width, specified as a scalar in meters. Normalized radiation pattern for microstrip patch antenna. Radiation pattern and gain the simple patch of fig. Electrical engineering stack exchange is a question and answer site for electronics and electrical engineering professionals, students, and enthusiasts. The bottom half of the sphere is ideally zero because it is beneath the ground plane where electric fields cannot radiate. Also the centre frequency of the antenna will changes in size of the ground plane. Understanding the behaviour of the microstrip patch. The patch antenna, microstrip transmission line and ground plane are made of high conductivity metal typically copper. To improve the performance of the patch antenna the surfacewave propagation is inhibited by constructing an electromagnetic bandgap structure 3, 4 in the ground plane of the patch antenna. Owing to its low height, low cost, high robustness, and monopolar radiation pattern, the wpa has been chosen as unit cell of the array that must be.
Ground plane size the larger the ground plane the higher the gain in general. This variant has better matching than the standard patch. Properties of a basic microstrip patch a microstrip or patch antenna is a low profile antenna that has a number of advantages over. Index terms directivity, far field, finite ground plane, monopole antenna, radiation pattern. Hplane represents the horizontal pattern, whereas vplane represents the vertical pattern. Owing to its low height, low cost, high robustness, and monopolar radiation pattern, the wpa has been chosen as unit cell of the array that must be placed on the. The radiated fields contributed by the induced current on the ground plane and the equivalent sources on the physical aperture yield the radiation pattern of the antenna. When a patch antenna is mounted off center on a ground plane, it will realize nonspherical radiation patterns. This corresponds to two vertical cuts of an apple type pattern which is the typical pattern of a gps patch antenna at cross angles to each other. Effects of finite ground plane on the radiation characteristics of a. The radiation pattern is relatively narrow for a simple antenna, which makes patch antennas desirable for assembly into arrays.
Patch antenna ground plane effect on radiation pattern at my current company, the rf engineer singular tells me that the antenna pattern will be pulled in the opposite direction this singular rf engineer is the smart guy. 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. Also, the excitation to the antenna is provided using feed lines connected through the patch. Design and analysis of a compact rectangular microstrip antenna. The radiation pattern, directive gain and input impedance are found to vary. Asymptotic method in prediction ofe plane radiation pattern of rectangular microstrip patch antennas an finite ground. In the following some results are reported for the patch moving on the diagonal of the ground plane, starting from the center see fig. In addition, by adding loads between the patch and the ground plane, such as pins and varactor diodes, adaptive elements with. Modern computeraided design even allows the arrays to follow curves con. As noted earlier, the two radiating slots create a twoelement array, which results in a narrower beam width than a simple slot which is like a dipole. One method used in patch antenna design is to introduce shorting pins from the patch to the ground plane at various locations.
The e plane radiation pattern of the antenna is shown to be very dependent on the size of the ground plane, and the results for two extreme cases are obtained in order to illustrate this effect. The sidebands are attenuated by more than 10 db either side of the main beam. Meanwhile, the introduction of slot at the ground plane produces a bidirectional radiation pattern. Special attention is paid to the shielding effect due to finite ground plane diffraction. In the representation of radiation pattern, we often come across different shapes, which indicate the major and minor radiation areas, by which the radiation efficiency of the antenna is known. For typical patch construction, the 3 db beamwidth is about 65 degrees, or 32. Influence of the ground plane structure on the radiation. Typical gain and axial ratio of a patch antenna with respect to ground plane size. 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. A thick dielectric substrate with dielectric constant within the range of 2. The radio waves from an antenna element that reflect off a ground plane appear to come from a mirror image of the antenna located on the other side of the ground plane. Finite ground plane effects on the radiation pattern of. The horizontal radiation pattern is a circle where the antenna radiates equally well in all directions.
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