High antenna gain is generally desirable for communications systems, whether terrestrial or based on satellites. Gain enhancement in microstrip patch antennas by replacing. Metamaterial enhances microstrip antenna gain microwaves. Antenna gain is defined as antenna directivity times a factor representing the radiation efficiency. To overcome this disadvantage and obtain an enhanced antenna gain, high permittivity dielectric constant substrate to fabricate compact microstrip patch antenna. Microstrip patch antennas have become the favorite of antenna designers because of its versatility and advantages of planar profile, ease of fabrication, compatibility with integrated circuit technology, and conformability with a shaped surface. Most antennas are resonant devices, which operate efficiently over a relatively narrow frequency band. Antenna basic concepts antenna an antenna is a device to transmit andor receive electromagnetic waves. Typical half wave patches have efficiencies well above 90%. Provide a physical understanding of the basic physical properties of microstrip antennas.
Pdf high gain microstrip mimo antenna for wireless applications. It was invented to allow convenient integration of an antenna and other driving circuitry of a communication system on a common printedcircuit board or a semiconductor chip carver and mink, 1981. The dielectric layer can be manipulated to fit different. Consider the side view of a patch antenna, shown in figure. To overcome the disadvantage of microstrip patch antenna and for multiband applications, fractal antenna geometry is useful 7,8. Their low profile design, often square or rectangular, allows them to be mounted to flat surfaces.
The antenna has a meanderline esa which is matched with an electrically small section of microstrip transmission line. The patch antenna, microstrip transmission line and ground plane are made of high conductivity metal typically copper. The proposed antenna will be useful for high gain systems requiring a broadband. Gain enhancement of a microstrip patch antenna using a. Most compact microstrip antenna designs show decreased antenna gain due to the antenna size reduction. Fundamental specifications of patch antennas radiation pattern a patch antenna radiates power in certain directions and we say that the antenna has directivity usually expressed in dbi. Pdf gain and bandwidth enhancement techniques in microstrip.
For a rectangular microstrip antenna, this requires the length of the antenna, l, to be about half a wavelength in the dielectric medium. Microstrip antennae are very simple in construction using a. Eferences fig7 3d polar plot of patch array antenna from the figure above, the aceived gain was 12. The different parameters required are radiation pattern, voltage standing wave ratio, reflection coefficients etc. The main goal of this paper is design a compact microstrip antenna module microstrip patch and fss structure. Figure 3 shows the ratio of the nearzone gain to the farzone gain for several n. Design and analysis of microstrip patch antenna arrays. Sabban, a new broadband stacked twolayer microstrip antenna, ieee aps int. Pdf high gain microstrip mimo antenna for wireless. Microstrip patch antennas kai fong lee, kwai man luk. Micros tip antennas, array antennas, reflector antennas and lens antennas. Wideband high gain fractal antenna for wireless applications. However the main lobe splits at the higher frequency band.
The use of metamaterials in single or multiple layers has been shown to contribute a great deal to the design of a high gain microstrip antenna at 10. When the antenna is excited, the waves generated within the dielectric undergo reflections and the energyis radiated from the edges of the metal patch,which is very low. The simulated results give significant improvement in terms of directive gain and bandwidth. The proposed antenna is suitable for specific applications, such as security and military systems, which require a narrow bandwidth and a small antenna size. Different substrates use in microstrip patch antennaa survey. These drawbacks can be overcome by taking care of some parameters in. Microstrip patch of rectangular or circular geometry etched on a grounded substrate is well known as printed antenna radiating along the broad side. Microstrip antennas have high q q 100 is common, which means that they have small bandwidths. Air substrate design is utilized to maximize the total efficiency of the circular patch operating in the fundamental tm110 mode. The unique property of the microstrip patch antenna is its twodimensional structure.
Gr crj the lu,12 functions, which enter into 16 and also into later formulas, are shown in figure 2. Antennas using patches as constitutive elements in an array are also possible. This efficiency quantifies the losses in the antenna and is defined as the ratio of radiated power pr to input power pi. Deschamps in 1953, but didnt become practical until the 1970s when it was developed further by researchers such as robert e. Effect of antenna size on gain, bandwidth, and efficiency. Its gain is about 3 db greater than a halfwave dipole, the highest gain of any dipole of any similar length. We will discuss later in this work more parameters of the antenna in connection with microstrip patch antenna like radiation pattern, efficiency, quality factor, directivity, gain, and more. Note that the maximum nearzone gain is essentially the same as the maximum farzone gain unless 3r antenna gain is defined as antenna directivity times a factor representing the radiation efficiency. Electromagnetic waves are often referred to as radio waves. Introduction in its most basic form, a microstrip patch antenna consists of a radiating patch on oneside of a dielectric substrate which has a ground plane on the other side for good antenna performance, a thick dielectric substrate having a low dielectric constant isdesirable since this provides better efficiency, larger bandwidth and better. The basics of patch antennas, updated orban microwave. An antenna must be tuned matched to the same frequency band as the radio. Microstrip antenna antenna radio transmission line.
Click here to go to our page on circular patch antennas new for september 2018. The antenna performance has been compared with different mimo systems presented in literature and gain of the proposed system is much higher than the gain of other systems for operating frequencies. Analysis and design of circular microstrip patch antenna at 5. Typical gain and bandwidth of conventional antenna elements. The design and simulation of this antenna has been done with the help of ansoft hfss. A patch antenna is a narrowband, widebeam antenna fabricated by etching the antenna element pattern in metal trace bonded to an insulating dielectric substrate, such as a printed circuit board, with a continuous metal layer bonded to the opposite side. The most common type of microstrip antenna is the patch antenna. The antenna radiation reflected lesser in antenna with fss layer by 7. Patterns are somewhat hemispherical, with a moderate directivity about 68 db is typical.
This work is mainly focused on increasing the gain as well as reducing the size of the unidirectional patch antenna. As there is currently an urgent need for graduate students and practicing engineers to gain an indepth understanding of this subject, this book was. A 54wave dipole antenna has a much lower but not purely resistive feedpoint impedance, which requires a matching network to the impedance of the transmission line. It plays a very significant role in todays world of wireless communication systems. Microstrip antenna an overview sciencedirect topics. Radiation efficiency is always lower than 100% so the antenna gain is always lower than antenna directivity. The fringing fields around the antenna can help explain why the microstrip antenna radiates. This unit will give the basic picture regarding microstrip antenna configurations, methods of analysis and some feeding techniques. If we use a substrate of a highpermittivity antenna gain that can be achieved is. Simulation results using cst studio showed that high gain 54 % increment and efficiency is increased to 97% have been achieved by the proposed antenna module ms and fss.
The aim of the project is to design a rectangular microstrip patch antenna with enhanced gain and bandwidth and study the effect of antenna dimensions length l, width w and substrate parameters relative dielectric constant. Dec 04, 2012 introduction in its most basic form, a microstrip patch antenna consists of a radiating patch on oneside of a dielectric substrate which has a ground plane on the other side for good antenna performance, a thick dielectric substrate having a low dielectric constant isdesirable since this provides better efficiency, larger bandwidth and better. Air cavity, front to back radiation, high gain, microstrip antenna. There are different types of antennas such as wire antennas, aperture antennas.
But despite of its bountiful advantages, patch antennas also experience some drawbacks viz low gain and narrow bandwidth. If the antenna had a 100% radiation efficiency, all directivity would be converted to gain. Microstrip antenna arrays with high efficiency one of the major advantages of microstrip an tennas is the simplicity of array construction j. The gain of a rectangular microstrip patch antenna with air dielectric can be very roughly estimated as follows.
The microstrip antenna is a relatively modern invention. The following figure1 shows the gain pattern of the antenna in the farfield. The goal of this project is to design and build high gain, low cost, low profile antenna that can be used for wifi applications that can compete with current high gain antennas already in the market. The width of the antenna, w, on the other hand, determines the level of the input impedance. Microstrip antennae are very simple in construction using a conventional microstrip fabrication technique. The fundamentals of patch antenna design and performance. Provide a physical and mathematical basis for understanding how microstrip antennas work. Easy to use in an array to increase the directivity. For feeding the microstrip patch antenna, coaxial probe feeding method is used having offset feeding position as 6mm. A highgain and highefficiency microstrip antenna is proposed and developed for microwave power transmission. The use of metamaterials in single or multiple layers has been shown to contribute a great deal to the design of a highgain microstrip antenna at 10. Abstract this paper presents the different techniques of gain improvement in microstrip patch antennas mpas. Since the length of the patch, half a wavelength is about the same as the length of resonant dipole, we get about.
Wideband high gain fractal antenna for wireless applications arpan desai1. Several designs for gain enhanced compact microstrip antenna with the loading of high dielectric superstrate or the inclusion of an amplifier type active circuitry have. Microstrip antenna is one of the most popular types of printed antenna. Properties of a basic microstrip patch a microstrip or patch antenna is a low profile antenna that has a number of advantages over other antennas it is lightweight, inexpensive, and easy to integrate with accompanying electronics. In the proposed work, antenna is simulated and fabricated for wireless applications using fr4 as the substrate, and it covers wide band with high gain. Simulation results using cst studio showed that high gain 54 % increment and efficiency is increased to 97% have been achieved by. The patch is of length l, width w, and sitting on top of a substrate some dielectric circuit board of thickness h with permittivity. Microstrip patch antennas or simply patch antenna are increasingly useful because the antenna is printed directly onto a circuit board. Easy to incorporate with other microstrip circuit elements and integrate into systems. An antenna plays a primary role in transmission and reception of electromagnetic waves. Additional benefits of patch antennas is that they are easily fabricated making them cost effective. The three patch geometries were investigated theoretically and reasonable values of resonant frequency return loss and gain are examined and compared. If the air spacing between the sensors and the human body is increased from 0mm to 5mm the antenna resonant frequency is shifted by 5%. The microstrip antenna can be thought of as a rectangular cavity with open sidewalls.
To overcome this disadvantage and obtain an enhanced antenna gain. Typical bandwidth element typical gain vswr microstrip antenna for improved bandwidth and directive gain is a challenge for researchers. Rectangular microstrip antenna with air cavity for high gain. As noted above, curved implementations can be made to conform to aircraft hulls. The radiation principle of this kind of microstrip configuration is based on the mirror. Provide an overview of some of the recent advances and trends in. Nov 25, 2016 in microstrip antenna, it is the fringing fields that are responsible for the radiation. As a flat antenna, arrays can have a large aperture, with corresponding high gain, but having low volume and weight. Such a microstrip patch antenna on high dielectric constant substrate suf. Today antenna designers are paying more focus on microstrip patch antennas, because of its numerous advantages in field of communication, such as high reliability, light weight, ease of fabrication etc. A low profile, unidirectional, dual layer, and narrow bandwidth microstrip patch antenna is designed to resonate at 2.
This paper proposes the design of a microstrip squarepatch antenna with enhanced bandwidth and directive gain. Pdf methods to design microstrip antennas for modern. The radiation pattern of microstrip or patch antenna is. The following image shows a microstrip or patch antenna.
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