An elliptical patch uwb antenna with reduced ground plane. The antennas feed is a through hole and reaches the bottom of board, where it meets a 50 ohm transmission line. Its good to have 1 wavelength ground plane size, but half wave. Effect of ground plane for enhancing the bandwidth and. Ceramic patch antennas are very popular because of the low costs and the huge variation of available sizes 40 x 40 mm down to 10 x 10 mm. 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. It has been observed as the slot length increases the resonant frequency.
The ground plane is used for directing the electromagnetic energy in the forward direction. It uses the standard formula, 234f mhz to calculate the element lengths. The enhancement of bandwidth and virtual size reduction are achieved without altering the size of the rectangular patch and nature of broadband radiation characteristics. The developed antenna was found to operate at an uwb frequency of 10. Effect of partial ground plane removal on the radiation. The horizontal radiation pattern is a circle where the antenna radiates equally well in all directions. Ease of fabrication and cost makes the groundplane antenna one of the popular antennas in communication systems. A groundplane antenna is a form of dipole antenna designed to work with an unbalanced feed line. Most radiation analyses of microstrip antenna are based on the assumption of an infinite ground plane. 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. An analytical technique to determine the effects of finite ground plane on the radiation characteristics of a microstrip antenna is presented. Since the image is 180 degrees outofphase with the antenna and effectively the same distance below ground as the antenna is above ground, it becomes obvious there will be a null along the ground with a horizontally polarized antenna. The simulation results show that the gain of a circular patch antenna varies with the ground plane size. Many numerical and measured results are presented to demonstrate the accuracy of.
The patch is attached to the ground plane by foam, providing firm connections and flexibility in bending. In the antenna in figure 1, the center conductor of a coaxial line serves as the feed probe. I used to work for a company that made electronics with gps patch antennas in them. This calculator can be used to design a quarter wave ground plane antenna, with radials. The source field from the radiating patch is calculated by two different methods. To investigate the effect of the ground plane size on the radiation characteristics of an msa, a conventional msa with a full metallic ground plane that operates in the dominant mode tm. You typically need a half wave ground plane to minimize frequency shift. In general, the ground plane size of the patch antenna should be 23 times the patch size, so as to maintain a good front and rear ratio.
A metal surface the larger and flatter, the better is required underneath the cb antenna to launch the signal out into the atmosphere. It has been observed as the slot length increases the resonant frequency shifted to the lower side by 19. There are usually four radials, three being a minimum, but you could use up to six. This chapter is devoted to exploring the interactions.
This paper presents effect of slots on microstrip patch antenna and its parameters. Here, the practical resonance shifts to the lower from the aforementioned 5. A groundplane antenna is more of less one half of the dipole and mounted above the ground plane. Does mounting a ground plane antenna upside down change.
How will the ground plane effect your embedded antenna. For example, some patch antennas are approximately half a wavelength on each side. As this antenna can only radiate above the ground plane, a monopole antenna will have a gain of 3 db over an equivalent dipole. Actual environments are different, and the ground plane is necessarily limited. The effects of varying the size of the ground plane of a rectangular microstrip antenna, which can excite te modes, are investigated in this paper.
The patch antenna, microstrip transmission line and ground plane are made of high conductivity metal typically copper. The induced currents on the ground plane and on the upper surface of the patch are determined from the discontinuity of the near field produced by the equivalent magnetic current source on the physical aperture of the patch. Because of the artificial ground provided by the radials, the height above ground should have little effect on this type of antenna. Influence of the ground plane structure on the radiation.
Patch antenna ground plane electrical engineering stack. The microstrip antennas have been designed on er 4. In the introduction it was mentioned that the enclosure and the components close to the embedded antenna like battery or display will interfere. The magnetic conducting patch and ground planes replace the electric conducting patch and ground plane. Citeseerx document details isaac councill, lee giles, pradeep teregowda. The effect is shown on bandwidth, gain, radiation pattern, return loss, axial ratio and size of an antenna. Amazons choice for ground plane antenna nagoya gpk01 21 radials nmo mount ground plane kit for base or field use, so239 connector, mounts to 2 pole, mast, pipe 4. Citeseerx effect of strip lined truncated ground plane. Patch antennas can show a very high gain, especially if they are mounted on top of a large ground plane 70 x 70 mm. I am designing a four layer board in which a patch antenna is used for a gps receiver. However when it is not possible to ground mount an antenna because of ground conditions or it is necessary to elevate the antenna, another solution is to use a ground plane. In this paper, we show the influence of the dimensions and the shape of the support. The gain of an omnidirectional antenna can be increased by narrowing the beamwidth in the vertical or elevation plane.
How to predict groundplane effects on patch antenna. The ground plane is a conductor and metals reflect electromagnetic radiation. The effect of simulated return loss, swept gain and radiation pattern of the proposed antenna have been obtained due to variation of slit dimensions. In this paper, the geometrical theory of diffraction gtd r. Study the ground plane effect of a multiband antenna for. If the ground plane is too small, the antenna shifts frequency, and thatll kill your sensitivity much more than the patterns going askew.
Chapter 2 dealt mainly with theoretical antennas in free space, completely removed from the influence of the ground. Ground mounted antennas are often very easy and convenient to use. This paper presents the effect of the slots in ground plane and patch on resonant frequency, impedance bandwidth, gain and side lobe. For a situation where the signals of interest are below the antenna in elevation e. The ideal patch is unbalanced, so you should have most of the surface current distribution on the patch surface. This assumes that there are no earth or grounding losses. The size of the ground plane of your embedded antenna will effect the performance. Patch antenna ground plane effect on radiation pattern. A typical gain pattern for a quarter wave ground plane antenna is. Whats the difference between a dipole and a ground plane. The bottom of patch is filled with ground but the layer adjacent to the ground filled layer is a power plane.
The slots on the patch or on the ground plane will help to design a. Patch antennas come in various shapes and sizes and consist of a patch of metal directly above a ground plane. Most antennas on the pcb are implemented as quarterwave antennas on a copper ground plane. In microstrip patch antennas, a radiating patch sits above a substrate and below the substrate there is a ground plane.
Making the ground plane larger also increases the gain, but as the ground plane size increases, diffraction near the edges plays less of a role and increasing the size of an already large ground plane has very little effect on gain. Effect of slots in ground plane and patch on microstrip. Once your ground plane gets large enough, the finite ground plane effects should be negligible. I currently work for a different company that makes electronics with gps patch antennas in them. 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 size of your pcb will have an effect of the performance of your selected embedded antenna as well. The main disadvantage of these antennas is their relatively large size compared to other types of antennas. The antenna is designed following the conventional design steps by applying duality theorem to it in order to excite the te modes. 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. As the name indicates the antenna ground plane acts as a. An antenna ground plane is not to be confused with an electrical ground.
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. The earth ground below the antenna, a conducting surface a least. In this article a broadband microstrip patch antenna is designed with slit incorporated in the rectangular ground plane. Effects of ground plane size on antenna gain electrical. The uniform geometrical theory of diffraction gtd is employed for calculating the edge diffracted fields from the finite ground plane of a microstrip antenna. What is the optmized size for a ground plane for micro. The design and analysis of printed antenna with the reduced ground plane effect, fed by micro strip line for ultra wide band uwb communication systems is presented. The basics of patch antennas, updated orban microwave. This study presents a new, simple method for reducing the backlobe radiation of a microstrip antenna msa by a partially removed ground plane of the antenna.
A typical mobile cb antenna does not transmit horizontally, it radiates in a downward pattern. The effects of ground 31 chapter 3 the effects of ground t he ground around and under an antenna is part of the environment in which any actual antenna must operate. Effect of ground plane size on a rectangular microstrip. The finite ground plane effect on the microstrip antenna. The below patterns are taken from scans of a 25mm25mm2mm patch on an extended 35mm groundplane. Note that the signal is now fed singleended and that the ground plane acts as the return path. How exactly a ground plane helps inproving antenna gain.
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