A groundplane antenna is a variant of the dipole antenna, designed for use with an unbalanced feed line such as coaxial cable. The uniform geometrical theory of diffraction is employed for calculating the diffracted fields from the edges of a slot antenna s finite ground plane. Patch and ground plane design of microstrip antennas by. It resembles a coaxial antenna whose lower section consists of straight elements called radials instead of a hollow conducting cylinder. A metal surface the larger and flatter, the better is required underneath the cb antenna to launch the signal out into the atmosphere. Even though the slot theory can only be employed for rectangular patch and copolar calcula tion, the gtd, however, can be combined with other theories, such as. Ictpituursi school on wireless networking for development the abdus salam international centre for theoretical physics ictp, trieste italy, 5 to 24 february 2007. It consists of a flat rectangular sheet or patch of metal, mounted over a larger sheet of metal called a ground plane. The performance properties of small, multiband, deviceintegrated antennas are significantly affected by the ground plane structure on which they are mounted. Apr 07, 2019 an antenna ground plane is not to be confused with an electrical ground. Patch with partial ground plane microstrip antenna is shown in fig.
The ground plane antenna packed with specially made gp antenna mounting hardware. The significance of ground plane size and antenna location. I am designing a four layer board in which a patch antenna is used for a gps receiver. A ground plane that is too small will result in a reduced front to back ratio. It is fed by a coaxial probe, which is connected to the patch through the ground plane. The uniform geometrical theory of diffraction gtd is employed for calculating the edge diffracted fields from the finite ground plane of a microstrip. Ushaped microstrip patch antenna with partial ground. My understanding is that when building or installing an antenna designed to operate over a ground plane e. As the name indicates the antenna ground plane acts as a simulated ground. I have looked online a bit and it seems to me that the general belief is that the larger the ground plane up to a certain extent, the better. One method used in patch antenna design is to introduce shorting pins from the patch to the ground plane at various locations.
In many cases, the timevarying current on the ground plane is the primary source of radiation that determines both the antenna s impedance and radiationpattern properties. The concept of infinite ground becomes even more important for arrays. This is close to optimum for back lobe suppression, and with the correctly designed associated patch radiating element, optimum for directivity. If the antenna is connected to a good earth ground, it is. This assumes that there are no earth or grounding losses. The finite ground plane effect on the microstrip antenna radiation. All models are mounted at the roof height approx 25 feet above the ground to provide the maximum communication range and perfect omni directional coverage. The gain for the ground plane is very nearly constant and equal to an isotropic antenna at low heights and real ground conditions. Microstrip patch antenna calculator patch antenna formula. The finite ground plane effect on microstrip antenna radiation pattern. The 14 wave ground plane or monopole antenna in this instance will be mounted on a mast and therefore a perfect ground pane will not be present. Antenna theory home antenna designers are always looking for creative ways to improve performance. Microstrip patch antenna is used in mobile handset due to simple look, lower cost, small size and light in weight. A groundplane antenna is a form of dipole antenna designed to work with an unbalanced feed line.
Jul 16, 20 the ground structure serves as the other. As this antenna can only radiate above the ground plane, a monopole antenna will have a gain of 3 db over an equivalent dipole. In antenna theory, a ground plane is a conducting surface large in comparison to the wavelength, such as the earth, which is connected to the transmitters ground wire and serves as a reflecting surface for radio waves. A slot will be placed on the ground plane and feed line will be placed on lower substrate. The patch antennas are popular for low profile applications at frequencies above 100mhz. Effects of ground plane size on a square microstrip patch antenna designed on.
Marquette university, 2011 microstrip antennas are a type of printed antenna which consists of a patch on top of a grounded substrate. A ground plane antenna is more of less one half of the dipole and mounted above the ground plane. The uniform geometrical theory of diffraction gtd is employed for calculating the edge diffracted fields from the finite ground plane of a microstrip antenna. The one pictured below is for receiving adsb aircraft signals on 1090mhz, again using scrap copper, but this time a purchased ntype chassis socket. I am trying to design a patch antenna, so i ran several fullwave simulations and increased the ground plane size each iteration, extracting the gain. An antenna ground plane is not to be confused with an electrical ground. Similarly as the slot width increases the resonant frequency. Micro strip antenna consists of a very thin metallic strip placed on a. Following equations or formula are used for this microstrip patch antenna calculator. The term has two different meanings in separate areas of electrical engineering. A major limitation for the performance of the patch antenna is the dielectric substrate. In a typical ground plane antenna the radials are bent down at 45 degrees and you trim the length of the radiator for lowest swr or better still best field strength at a distance.
The antenna is simulated with fr4 substrate with the relative dielectric constant of 4. Influence of the ground plane structure on the radiation pattern of. The image antenna for a dipole over perfect earth is a dipole at the same distance below. Patch antenna ground plane electrical engineering stack. For this purpose, defected ground structure dgs has been employed to shift the resonance frequency of an initial microstrip antenna from 5. The ground plane should extend beyond the edges of the patch by at least 2 to 3 times the board thickness for proper operation. A typical mobile cb antenna does not transmit horizontally, it radiates in a downward pattern. The proposed single layered antenna is advantageous over some recently reported designs, with comparable ibw, realized gain value, lowcost, and simple design technique.
The antenna s feed is a through hole and reaches the bottom of board, where it meets a 50 ohm transmission line. 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. Ground plan element dimensions for various local australian and some international amateur radio bands with 4nec2 an nec based antenna modelling and optimizing computer application the proposed 14. A ground plane antenna is a variant of the dipole antenna, designed for use with an unbalanced feed line such as coaxial cable. The source field from the radiating patch is calculated by two different methods.
Ground currents all around the antenna make the image work. But for uwb it also improves s11 at lower frequency. In my opinion, an optimiztion for the choice for the size of ground plane should be taken into consideration for any given antenna design. The uniform geometrical theory of diffraction is employed for calculating the diffracted fields from the edges of a slot antennas finite ground plane. Miniaturized microstrip patch antenna with defected ground. Ground plane monopole and marconi antennas are one quarter wavelength high. As the number of elements increase the size of the ground plane increases dramatically as the space on the ground between the elements also needs to be meshed. The size of the ground plane is driven by patch antenna theory, and as i indicated, it should be 1 wavelength long on a side, or around a 1 wavelength diameter disc if round. Antenna above perfectly conducting plane surface tangential electrical field component 0. For a situation where the signals of interest are below the antenna in elevation e. Apart from the list appeared above we are experts to design and supply the ground plane antennas for out of bands antenna.
This method employs ground plane between two substrates. Making the ground plane larger also increases the gain, but as the ground plane size. Analysis of an airspaced patch antenna near 1800 mhz. Think of the ground plane being a metal roof of a vehicle and place the rubber duck antenna in the center with the antenna top end pointing straight up. Ease of fabrication and cost makes the groundplane antenna one of the popular antennas in communication systems. Most radiation analyses of microstrip antenna are based on the assumption of an infinite ground plane. This variant has better matching than the standard patch. While image theory isnt usually considered in the case of the patch antenna.
The aim of this work is to miniaturize a microstrip patch antenna resonating at 3 ghz. Many comparisons between theory and experimentation are presented. Note that the better ground conditions give a lower angle. The ground or radials are the other half of the antenna. Here, the practical resonance shifts to the lower from the aforementioned 5. Actual environments are different, and the ground plane is necessarily limited.
If the ground plane is adequately sized and conductive, the performance of the ground plane is equivalent to a vertically mounted. These are preliminary notes, intended only for distribution among the participants. For a simple patch antenna the size of gorund plane significantly affects the return loss at resonances. This calculator can be used to design a quarter wave ground plane antenna, with radials. As we know the current distribution on the ground plane of the conventional patch antenna mainly concentrates just under the patch, as shown in figure 3, which is the vector current distribution of the resonant frequency 5.
Blog antenna ground plane calculation arcadian antenna. The finite ground plane effect on the microstrip antenna. The basics of patch antennas, updated orban microwave. Effect of slots in ground plane and patch on microstrip antenna. The bottom of patch is filled with ground but the layer adjacent to the ground filled layer is a power plane. It consists of area of metallization supported above a ground plane by a thin dielectric substrate and fed against the ground at an appropriate location. The patch antenna can be modeled simply in fdtd since the tangential electric fields on a perfect are zero, you simply designate the location of the patch, and have the tangential efields zeroed out where you want the patch, ground plane and microstrip transmission line to reside. From this structure, it is clear that if the antenna is excited, there will be conductive currents on the patch and the middle strip, then generating the coupling currents among the strips and the patch as well as between the neighboring strips. The wire patch antenna, 14 presents the structure of a classical microstrip antenna with a roof of arbitrary shape figure 1. In this case, its a multiband antenna the customer is using it can be used from 700 mhz 2700 mhz so the ground plane required could be anywhere from 464 square inches. The distance between the patch and the ground plane the. Does mounting a ground plane antenna upside down change.
Measured and simulated results are presented to illustrate the edge effect of a finite ground plane on a slot antenna s return loss and radiation pattern. Measured and simulated results are presented to illustrate the edge effect of a finite ground plane on a slot antennas return loss and radiation pattern. Typically the height h is much smaller than the wavelength of operation, but not. In this antenna, one corner of the patch or sometimes one edge is grounded with a ground pin. The patch is of length l, width w, and sitting on top of a substrate some dielectric circuit board of thickness h with permittivity.
Many numerical and measured results are presented to demonstrate the. The ag series is range of omni directional unity gain ground plane antennas that are. Design of a meandered line microstrip antenna with a. The ground pane will be simulated as is normally the case with a number of metallic elements extending out horizontally from the base of the monopole element and connected to the shield of the coax. A groundplane antenna is more of less one half of the dipole and mounted above the ground plane. In electrical engineering, a ground plane is an electrically conductive surface, usually connected to electrical ground. Meanwhie the takeoff angle appears to be in the range of 15 to 20 degrees for most cases at low heights.
Design and improvement of microstrip patch antenna. When ground plane is near to radiator then some current is induced. The amountsize of the groundplane required for the optimal performance of a monopole antenna is determined by the frequency you are transmittingreceiving at. A typical gain pattern for a quarter wave ground plane antenna is. To illustrate how this may help, two instances will be illustrated. The proposed dgs is incorporated in the ground plane under the patch antenna to. The image antenna just represents all of the currents induced in the ground all around the antenna. It is possible to simulate this function by replacing the real earth. Here, the solid ground plane is assumed to be sliced into 5 strips which they are symmetrical on current direction as shown in figure 1c. The particularity of this antenna is that it has at least one shorting wire connected between the patch and the ground plane. That image isnt an actual current or dipole at the position of the image antenna.
Below is a quarter wave ground plane antenna i made for 23cm, 1296mhz which is made from offcuts of household mains copper wire and a scrap bnc socket from the junk box. Antenna experts manufactures ground plane antenna for 3066 mhz. The basic structure of the microstrip patch antenna is shown in figure 1. Modeling infinite ground plane in antennas and arrays. Many numerical and measured results are presented to demonstrate the accuracy of. What is the optmized size for a ground plane for micro strip antenna. Ushaped microstrip patch antenna with partial ground plane. Effect of a finite ground plane on microstripfed cavity. Analysis of an airspaced patch antenna near 1800 mhz hermine n. In printed circuit boards, a ground plane is a large area of copper foil on th. The thickness of the ground plane or of the microstrip is not critically important.
In reality it is very difficult to get an antenna rf grounding system that is lossless and it is accordingly difficult to fully realise this gain. A microstrip patch or array with infinite ground plane is a theoretical antenna, but patch with finite ground plane is of practical interest. In this article, a linearly polarized meandered line planar antenna with dgs incorporated in the ground plane is presented. A ground plane antenna is a form of dipole antenna designed to work with an unbalanced feed line. This antenna is often built of printed circuit board material and the substrate makes up the patch antennas dielectric.
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. The patch antenna, microstrip transmission line and ground plane are made of high conductivity metal typically copper. This indicates the size reduction of slotted patch antenna is more than slotted ground plane patch. These are very low size antennas having low radiation. Effects of ground plane size on antenna gain electrical. Whats the difference between a dipole and a ground plane. A patch antenna is a type of radio antenna with a low profile, which can be mounted on a flat surface.
So calculate the length of the radiator for your frequency then add a few inches. What is the impact of image current from ground plane on. The main focus of this paper is to improve band width so that patch antenna is used for wide band. In this paper, we show the influence of the dimensions and the shape of the support. The size for the ground plane depends on many issues.
Ease of fabrication and cost makes the ground plane antenna one of the popular antennas in communication systems. Here the previously designed 8 element array with corporate feed, as shown in figure 6. A metal patch mounted at a ground level with a dielectric material inbetween constitutes a micro strip or patch antenna. They are the original type of microstrip antenna described by howell in 1972. There are usually four radials, three being a minimum, but you could use up to six.
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