Modeling infinite ground plane in antennas and arrays. A typical mobile cb antenna does not transmit horizontally, it radiates in a downward pattern. It consists of a flat rectangular sheet or patch of metal, mounted over a larger sheet of metal called a ground plane. Design of a meandered line microstrip antenna with a. For a situation where the signals of interest are below the antenna in elevation e. The term has two different meanings in separate areas of electrical engineering. 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. This calculator can be used to design a quarter wave ground plane antenna, with radials. 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.
What is the impact of image current from ground plane on. Analysis of an airspaced patch antenna near 1800 mhz. Micro strip antenna consists of a very thin metallic strip placed on a. For this purpose, defected ground structure dgs has been employed to shift the resonance frequency of an initial microstrip antenna from 5. Typically the height h is much smaller than the wavelength of operation, but not. For a simple patch antenna the size of gorund plane significantly affects the return loss at resonances. In this antenna, one corner of the patch or sometimes one edge is grounded with a ground pin. Effect of slots in ground plane and patch on microstrip antenna. Many numerical and measured results are presented to demonstrate the. Analysis of an airspaced patch antenna near 1800 mhz hermine n. Ground plane monopole and marconi antennas are one quarter wavelength high. 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. I am designing a four layer board in which a patch antenna is used for a gps receiver.
The wavelength corresponds to the velocity speed of the wave divided by its frequency. 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. A slot will be placed on the ground plane and feed line will be placed on lower substrate. The performance properties of small, multiband, deviceintegrated antennas are significantly affected by the ground plane structure on which they are mounted. Ground currents all around the antenna make the image work. It is fed by a coaxial probe, which is connected to the patch through the ground plane. 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 thickness of the ground plane or of the microstrip is not critically important. 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. 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.
There are usually four radials, three being a minimum, but you could use up to six. The uniform geometrical theory of diffraction gtd is employed for calculating the edge diffracted fields from the finite ground plane of a microstrip. A microstrip patch or array with infinite ground plane is a theoretical antenna, but patch with finite ground plane is of practical interest. As the name indicates the antenna ground plane acts as a simulated ground.
The size for the ground plane depends on many issues. In electrical engineering, a ground plane is an electrically conductive surface, usually connected to electrical ground. The one pictured below is for receiving adsb aircraft signals on 1090mhz, again using scrap copper, but this time a purchased ntype chassis socket. Microstrip patch antenna calculator patch antenna formula.
A metal patch mounted at a ground level with a dielectric material inbetween constitutes a micro strip or patch antenna. The finite ground plane effect on the microstrip antenna radiation. If the antenna is connected to a good earth ground, it is. Following equations or formula are used for this microstrip patch antenna calculator. The antenna s feed is a through hole and reaches the bottom of board, where it meets a 50 ohm transmission line. This variant has better matching than the standard patch. But for uwb it also improves s11 at lower frequency. A ground plane antenna is a variant of the dipole antenna, designed for use with an unbalanced feed line such as coaxial cable. Similarly as the slot width increases the resonant frequency. Jul 16, 20 the ground structure serves as the other.
This antenna is often built of printed circuit board material and the substrate makes up the patch antennas dielectric. 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. That image isnt an actual current or dipole at the position of the image antenna. The wire patch antenna, 14 presents the structure of a classical microstrip antenna with a roof of arbitrary shape figure 1. If the ground plane is adequately sized and conductive, the performance of the ground plane is equivalent to a vertically mounted. Influence of the ground plane structure on the radiation. 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. The uniform geometrical theory of diffraction is employed for calculating the diffracted fields from the edges of a slot antennas finite ground plane.
The main focus of this paper is to improve band width so that patch antenna is used for wide band. Effects of ground plane size on antenna gain electrical. A ground plane that is too small will result in a reduced front to back ratio. 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 antenna is simulated with fr4 substrate with the relative dielectric constant of 4. The basics of patch antennas, updated orban microwave. Influence of the ground plane structure on the radiation pattern of.
Whats the difference between a dipole and a ground plane. An antenna ground plane is not to be confused with an electrical ground. Patch antenna ground plane electrical engineering stack. 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. Patch and ground plane design of microstrip antennas by. This assumes that there are no earth or grounding losses. One method used in patch antenna design is to introduce shorting pins from the patch to the ground plane at various locations. 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. In my opinion, an optimiztion for the choice for the size of ground plane should be taken into consideration for any given antenna design. 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. When ground plane is near to radiator then some current is induced. This paper presents the effect of the slots in ground plane and patch on resonant frequency, impedance bandwidth, gain and side lobe.
In printed circuit boards, a ground plane is a large area of copper foil on th. These are very low size antennas having low radiation. It resembles a coaxial antenna whose lower section consists of straight elements called radials instead of a hollow conducting cylinder. Antenna above perfectly conducting plane surface tangential electrical field component 0. This method employs ground plane between two substrates. 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. Patch with partial ground plane microstrip antenna is shown in fig. Antenna experts manufactures ground plane antenna for 3066 mhz.
To illustrate how this may help, two instances will be illustrated. Ease of fabrication and cost makes the ground plane antenna one of the popular antennas in communication systems. The distance between the patch and the ground plane the. It is possible to simulate this function by replacing the real earth. This is close to optimum for back lobe suppression, and with the correctly designed associated patch radiating element, optimum for directivity. The amountsize of the groundplane required for the optimal performance of a monopole antenna is determined by the frequency you are transmittingreceiving at. As this antenna can only radiate above the ground plane, a monopole antenna will have a gain of 3 db over an equivalent dipole. The ground or radials are the other half of the antenna. Apr 07, 2019 an antenna ground plane is not to be confused with an electrical ground. The ground plane antenna packed with specially made gp antenna mounting hardware. The finite ground plane effect on the microstrip antenna. A ground plane antenna is a form of dipole antenna designed to work with an unbalanced feed line.
In this article, a linearly polarized meandered line planar antenna with dgs incorporated in the ground plane is presented. The patch antenna, microstrip transmission line and ground plane are made of high conductivity metal typically copper. 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. 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 aim of this work is to miniaturize a microstrip patch antenna resonating at 3 ghz. A metal surface the larger and flatter, the better is required underneath the cb antenna to launch the signal out into the atmosphere. The significance of ground plane size and antenna location. The ag series is range of omni directional unity gain ground plane antennas that are.
The particularity of this antenna is that it has at least one shorting wire connected between the patch and the ground plane. A groundplane antenna is more of less one half of the dipole and mounted above the ground plane. Many comparisons between theory and experimentation are presented. Effect of a finite ground plane on microstripfed cavity. Microstrip patch antenna is used in mobile handset due to simple look, lower cost, small size and light in weight. Note that the better ground conditions give a lower angle. The uniform geometrical theory of diffraction is employed for calculating the diffracted fields from the edges of a slot antenna s finite ground plane. Here the previously designed 8 element array with corporate feed, as shown in figure 6. 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. Antenna theory home antenna designers are always looking for creative ways to improve performance. These are preliminary notes, intended only for distribution among the participants. This indicates the size reduction of slotted patch antenna is more than slotted ground plane patch. 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. My understanding is that when building or installing an antenna designed to operate over a ground plane e.
Ushaped microstrip patch antenna with partial ground plane. The patch is of length l, width w, and sitting on top of a substrate some dielectric circuit board of thickness h with permittivity. Making the ground plane larger also increases the gain, but as the ground plane size. 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.
So calculate the length of the radiator for your frequency then add a few inches. Many numerical and measured results are presented to demonstrate the accuracy of. A major limitation for the performance of the patch antenna is the dielectric substrate. The gain for the ground plane is very nearly constant and equal to an isotropic antenna at low heights and real ground conditions. Design and improvement of microstrip patch antenna. 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.
Here, the practical resonance shifts to the lower from the aforementioned 5. A groundplane antenna is a form of dipole antenna designed to work with an unbalanced feed line. Apart from the list appeared above we are experts to design and supply the ground plane antennas for out of bands antenna. The proposed single layered antenna is advantageous over some recently reported designs, with comparable ibw, realized gain value, lowcost, and simple design technique.
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. The bottom of patch is filled with ground but the layer adjacent to the ground filled layer is a power plane. A ground plane antenna is more of less one half of the dipole and mounted above the ground plane. While image theory isnt usually considered in the case of the patch antenna. Ictpituursi school on wireless networking for development the abdus salam international centre for theoretical physics ictp, trieste italy, 5 to 24 february 2007.
The image antenna just represents all of the currents induced in the ground all around the antenna. Effects of ground plane size on a square microstrip patch antenna designed on. A typical gain pattern for a quarter wave ground plane antenna is. A patch antenna is a type of radio antenna with a low profile, which can be mounted on a flat surface. 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 patch antennas are popular for low profile applications at frequencies above 100mhz. What is the optmized size for a ground plane for micro strip antenna. The antennas feed is a through hole and reaches the bottom of board, where it meets a 50 ohm transmission line. 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. Blog antenna ground plane calculation arcadian antenna. The concept of infinite ground becomes even more important for arrays. They are the original type of microstrip antenna described by howell in 1972. Ushaped microstrip patch antenna with partial ground. Does mounting a ground plane antenna upside down change.
Meanwhie the takeoff angle appears to be in the range of 15 to 20 degrees for most cases at low heights. Ease of fabrication and cost makes the groundplane antenna one of the popular antennas in communication systems. It is found that for a monopole antenna like a quarter wavelength vertical, the ground acts as a plane to reflect the radio waves so that an image of the top half of the antenna is seen in the earth. A groundplane antenna is a variant of the dipole antenna, designed for use with an unbalanced feed line such as coaxial cable. The image antenna for a dipole over perfect earth is a dipole at the same distance below. 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. Actual environments are different, and the ground plane is necessarily limited. In this paper, we show the influence of the dimensions and the shape of the support.
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