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