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 antenna, microstrip transmission line and ground plane are made of high conductivity metal typically copper. While image theory isnt usually considered in the case of the patch antenna. To illustrate how this may help, two instances will be illustrated. The ground or radials are the other half of the antenna. 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. 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. So calculate the length of the radiator for your frequency then add a few inches. The term has two different meanings in separate areas of electrical engineering.
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. Whats the difference between a dipole and a ground plane. The proposed single layered antenna is advantageous over some recently reported designs, with comparable ibw, realized gain value, lowcost, and simple design technique. Many numerical and measured results are presented to demonstrate the accuracy of. Effect of slots in ground plane and patch on microstrip antenna. 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 finite ground plane effect on microstrip antenna radiation pattern. The bottom of patch is filled with ground but the layer adjacent to the ground filled layer is a power plane. A metal surface the larger and flatter, the better is required underneath the cb antenna to launch the signal out into the atmosphere. Miniaturized microstrip patch antenna with defected ground. Apr 07, 2019 an antenna ground plane is not to be confused with an electrical ground.
Ictpituursi school on wireless networking for development the abdus salam international centre for theoretical physics ictp, trieste italy, 5 to 24 february 2007. These are very low size antennas having low radiation. The gain for the ground plane is very nearly constant and equal to an isotropic antenna at low heights and real ground conditions. This antenna is often built of printed circuit board material and the substrate makes up the patch antennas dielectric. This calculator can be used to design a quarter wave ground plane antenna, with radials. Jul 16, 20 the ground structure serves as the other. Analysis of an airspaced patch antenna near 1800 mhz. 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 basics of patch antennas, updated orban microwave. Meanwhie the takeoff angle appears to be in the range of 15 to 20 degrees for most cases at low heights. Many numerical and measured results are presented to demonstrate the. The uniform geometrical theory of diffraction is employed for calculating the diffracted fields from the edges of a slot antennas finite ground plane. Typically the height h is much smaller than the wavelength of operation, but not. For this purpose, defected ground structure dgs has been employed to shift the resonance frequency of an initial microstrip antenna from 5.
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. The wavelength corresponds to the velocity speed of the wave divided by its frequency. My understanding is that when building or installing an antenna designed to operate over a ground plane e. A groundplane antenna is a form of dipole antenna designed to work with an unbalanced feed line.
Ushaped microstrip patch antenna with partial ground. Effects of ground plane size on antenna gain electrical. It consists of a flat rectangular sheet or patch of metal, mounted over a larger sheet of metal called a ground 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. In this antenna, one corner of the patch or sometimes one edge is grounded with a ground pin. The ground plane antenna packed with specially made gp antenna mounting hardware. Note that the better ground conditions give a lower angle. In printed circuit boards, a ground plane is a large area of copper foil on th. This variant has better matching than the standard patch. 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. 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. 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.
Blog antenna ground plane calculation arcadian antenna. The uniform geometrical theory of diffraction gtd is employed for calculating the edge diffracted fields from the finite ground plane of a microstrip. Micro strip antenna consists of a very thin metallic strip placed on a. 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. 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. Antenna theory home antenna designers are always looking for creative ways to improve performance. For a simple patch antenna the size of gorund plane significantly affects the return loss at resonances.
The image antenna for a dipole over perfect earth is a dipole at the same distance below. An antenna ground plane is not to be confused with an electrical ground. 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. Effects of ground plane size on a square microstrip patch antenna designed on. Here the previously designed 8 element array with corporate feed, as shown in figure 6. Marquette university, 2011 microstrip antennas are a type of printed antenna which consists of a patch on top of a grounded substrate.
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 ground plane should extend beyond the edges of the patch by at least 2 to 3 times the board thickness for proper operation. Effect of a finite ground plane on microstripfed cavity. The finite ground plane effect on the microstrip antenna radiation. A typical gain pattern for a quarter wave ground plane antenna is. Microstrip patch antenna is used in mobile handset due to simple look, lower cost, small size and light in weight. Influence of the ground plane structure on the radiation.
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. Most radiation analyses of microstrip antenna are based on the assumption of an infinite ground plane. 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. Actual environments are different, and the ground plane is necessarily limited. 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. Ground currents all around the antenna make the image work. The amountsize of the groundplane required for the optimal performance of a monopole antenna is determined by the frequency you are transmittingreceiving at.
Similarly as the slot width increases the resonant frequency. The proposed dgs is incorporated in the ground plane under the patch antenna to. A patch antenna is a type of radio antenna with a low profile, which can be mounted on a flat surface. What is the optmized size for a ground plane for micro strip antenna. What is the impact of image current from ground plane on. The antenna is simulated with fr4 substrate with the relative dielectric constant of 4. The patch antennas are popular for low profile applications at frequencies above 100mhz.
A typical mobile cb antenna does not transmit horizontally, it radiates in a downward pattern. 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. It is possible to simulate this function by replacing the real earth. 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 antenna ground plane electrical engineering stack.
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 significance of ground plane size and antenna location. 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. Ground plane monopole and marconi antennas are one quarter wavelength high.
It is fed by a coaxial probe, which is connected to the patch through the ground plane. The concept of infinite ground becomes even more important for arrays. Does mounting a ground plane antenna upside down change. The antennas feed is a through hole and reaches the bottom of board, where it meets a 50 ohm transmission line. Modeling infinite ground plane in antennas and arrays. If the ground plane is adequately sized and conductive, the performance of the ground plane is equivalent to a vertically mounted. 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.
This assumes that there are no earth or grounding losses. Patch with partial ground plane microstrip antenna is shown in fig. Analysis of an airspaced patch antenna near 1800 mhz hermine n. As this antenna can only radiate above the ground plane, a monopole antenna will have a gain of 3 db over an equivalent dipole. This paper presents the effect of the slots in ground plane and patch on resonant frequency, impedance bandwidth, gain and side lobe. Patch and ground plane design of microstrip antennas by. The source field from the radiating patch is calculated by two different methods. The size for the ground plane depends on many issues. Ease of fabrication and cost makes the groundplane antenna one of the popular antennas in communication systems. The main focus of this paper is to improve band width so that patch antenna is used for wide band. 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.
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 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. 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. Influence of the ground plane structure on the radiation pattern of. The thickness of the ground plane or of the microstrip is not critically important. The antenna s feed is a through hole and reaches the bottom of board, where it meets a 50 ohm transmission line. 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. A ground plane antenna is more of less one half of the dipole and mounted above the ground plane. Here, the practical resonance shifts to the lower from the aforementioned 5. There are usually four radials, three being a minimum, but you could use up to six. Design of a meandered line microstrip antenna with a.
Design and improvement of microstrip patch antenna. Making the ground plane larger also increases the gain, but as the ground plane size. The wire patch antenna, 14 presents the structure of a classical microstrip antenna with a roof of arbitrary shape figure 1. A major limitation for the performance of the patch antenna is the dielectric substrate. A ground plane antenna is a form of dipole antenna designed to work with an unbalanced feed line. This method employs ground plane between two substrates. Ushaped microstrip patch antenna with partial ground plane. But for uwb it also improves s11 at lower frequency. In this article, a linearly polarized meandered line planar antenna with dgs incorporated in the ground plane is presented. One method used in patch antenna design is to introduce shorting pins from the patch to the ground plane at various locations.
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. Microstrip patch antenna calculator patch antenna formula. The finite ground plane effect on the microstrip antenna. This indicates the size reduction of slotted patch antenna is more than slotted ground plane patch.
The basic structure of the microstrip patch antenna is shown in figure 1. Many comparisons between theory and experimentation are presented. Following equations or formula are used for this microstrip patch antenna calculator. 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. The one pictured below is for receiving adsb aircraft signals on 1090mhz, again using scrap copper, but this time a purchased ntype chassis socket. A groundplane antenna is a variant of the dipole antenna, designed for use with an unbalanced feed line such as coaxial cable. The particularity of this antenna is that it has at least one shorting wire connected between the patch and the ground plane. These are preliminary notes, intended only for distribution among the participants. Ease of fabrication and cost makes the ground plane antenna one of the popular antennas in communication systems. 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 image antenna just represents all of the currents induced in the ground all around the antenna.
The aim of this work is to miniaturize a microstrip patch antenna resonating at 3 ghz. When ground plane is near to radiator then some current is induced. As the name indicates the antenna ground plane acts as a simulated ground. It resembles a coaxial antenna whose lower section consists of straight elements called radials instead of a hollow conducting cylinder. In this paper, we show the influence of the dimensions and the shape of the support. I am designing a four layer board in which a patch antenna is used for a gps receiver.
A groundplane antenna is more of less one half of the dipole and mounted above the ground plane. Antenna experts manufactures ground plane antenna for 3066 mhz. The performance properties of small, multiband, deviceintegrated antennas are significantly affected by the ground plane structure on which they are mounted. A ground plane that is too small will result in a reduced front to back ratio. They are the original type of microstrip antenna described by howell in 1972. This is close to optimum for back lobe suppression, and with the correctly designed associated patch radiating element, optimum for directivity. In electrical engineering, a ground plane is an electrically conductive surface, usually connected to electrical ground. The distance between the patch and the ground plane the. The ag series is range of omni directional unity gain ground plane antennas that are. That image isnt an actual current or dipole at the position of the image antenna.