Design consideration of microstrip patch antenna citeseerx. Microstrip patch antenna has a ground plane on the one 1. Three types of feeding arrangements are discussed here. This truncation generates two degenerate resonances which result in a flattened frequency response of the input impedance. Florida state university libraries electronic theses, treatises and dissertations the graduate school 2004 design of a compact microstrip patch antenna for use in wirelesscellular devices punit s. A novel seriesfed microstrip patch array antenna for 3739 ghz beamforming is proposed. Simulations and tests shows that the antenna is circular polarized and have a. It is possible to match the patch antenna from below 30. What are the exact materials used in designing a microstrip. The electric field is assumed to act entirely in the zdirection and to be a. Microstrip patch antenna arrays are widely used for the purpose of focusing the radiation from an antenna in the near field fresnel region.
In addition to compatibility with integrated circuit technology, microstrip antenna systems offer other benefits such as thin profile, light weight, low cost and conformability to a shaped surface. Microstrip line feed, coaxial probe feed, and aperturecoupled feed techniques. Microstrip patch antennas have become the favorite of antenna designers because of their versatility and having the advantages of planar profile, ease of fabrication, compatibility with integrated circuit technology, and conformability with a shaped surface. Also called patch antennas one of the most useful antennas at microwave frequencies f 1 ghz. A variety of design parameters can be optimized for improved bandwidth and impedance matching.
The microstrip antenna will feed the patch offset from the center, as shown in figure 1. Hence, engineers usually only bother talking about one or the other. This paper proposes a compact microstrip patch antenna for operating in 2. E field curve in cst for patch antennapatch antenna. In transmission, a radio transmitter supplies an electric current to the antennas terminals, and the antenna radiates the energy from the current as electromagnetic waves radio waves. As a result, these antennas are most often used as receive antennas, where impedance mismatch loss can be tolerated. The simulated results of active antennas show that the designed antennas have proper radiation characteristics at its desired.
Equivalent circuit of magnetoelectric dipole antenna with lprobe feed. The basics of patch antennas, updated orban microwave. Jelinek are with the department of electromagnetic field, faculty of electrical engineering, czech technical university in prague, technicka 2, 16627, prague, czech republic email. May 25, 2019 slot antenna differs with patch antenna in many aspects. This means that on each side of the feed line there should be a distance of 12 the microstrip width on each side of the microstrip between the microstrip feed line and the patch antenna. The transient pulse will be of the form given by exptt0t 2, where t0 is the time delay and will be 45 ps picoseconds, 1012, and t is a parameter that controls the rate of rise and fall, which is 15 ps. It usually consists of a metal patch on top of a grounded dielectric substrate. This low current value at the feed explains in part why the impedance is high. Cross section of a patch antenna in its basic form.
As a result, this transmission line cannot support pure. The antenna feed may refer to all components connecting the antenna to the transmitter or receiver, such as an impedance matching network in addition to the transmission line. Dec 25, 2017 e field curve in cst for patch antenna. The large selfresonant loop antenna has a circumference close to one wavelength of the operating frequency and so is resonant at that frequency. The basics of operation is to generate a magnetic field out of phase with an electric field with a ratio that impedance matches with the air 377 ohms. Generally, patch antenna has a shape of rectangle, and it can be feed with copper cable. A loop antenna is a radio antenna consisting of a loop or coil of wire, tubing, or other electrical conductor usually fed by a balanced source or feeding a balanced load. After finding the patch size the antenna feed line should be designed. The distribution of the electric field of a rectangular patch when excited in its. The small bandwidth, however, is adequate in a large class of communication applications. Near field focusing of rectangular microstrip patch antenna array. Patch antennas were used because of their ease of integration with printed circuit board pcb technology. Antenna,microstrip, patch antenna,coaxial cable,radio,microwave engineering,probe feed,cst,coaxia.
This work analyses the performance of different feeding techniques for rectangular microstrip patch antennas used in wireless communications applications, such as in wimax and lte technologies. Design and performance analysis of inset feed microstrip. A half wave centre fed dipole antenna in free space has an impedance of 73. Proximity coupled patch antenna with microstrip feed 212.
The natural input impedance of a patch antenna dependent on where within the patch the feed is located. Design of circular polarized dual band patch antenna. Geometries, current and electric field distributions of the circular patch antennas excited by different feeds. What is the difference between slot antenna and patch. Microstrip antennas have high q q 100 is common, which means that they have small bandwidths.
These magnetic fields ultimately give rise to the antenna radiation, and since they are somewhat immune to the human body, loop antennas tend to be much more robust in terms of performance. The final dimensions for the feed structure, slot and patch elements are detailed in figures 3a 3d. The theory of antenna operation can be seen in the following videos. Actually, slot antenna is a radiating element formed by a slot in a metallic surface. Jun 22, 2018 simulate and analyze a rectangular patch antenna using ansys hfss, including return loss and 3d radiation fields. An exploded view of a single patch acmsa can be seen in figure 1.
The center conductor of a coax serves as the feed probe to couple electromagnetic energy in andor out of the patch. Microstrip patch antennas can be fed by a variety of methods. Slot antenna differs with patch antenna in many aspects. Their low profile design, often square or rectangular, allows them to be mounted to flat surfaces. The patch antenna element developed for the phased array sar pharus operating at 5. E field curve in cst for patch antennapatch antenna design. How is the magnetic field radiated in a microstrip patch antenna. Simple and approximate expressions for the radiated electric field components of a microstrip antenna are given by carver and mink 1981. The small loop antenna is a closed loop as shown in figure 1.
As the voltage drops to zero it leaves a traveling electric field that is then pushed outwards and away from the antenna as the voltage rises again in the opposite polarity. Microstrip patch antennas or simply patch antenna are increasingly useful because the antenna is printed directly onto a circuit board. Design of a magnetoelectric dipole antenna for fm radio. Introduction in recent years there is a need for more compact antennas due to rapid decrease in size of personal communication devices. Feedline radiation is isolated from patch radiation higher bandwidth is possible since probe inductance is eliminated allowing for a thick substrate, and also a doubleresonance can be created allows for use of different substrates to optimize antenna and feedcircuit performance disadvantages. Additional benefits of patch antennas is that they are easily fabricated making them cost effective. What is the difference between slot antenna and patch antenna. Note that a quarterwave length transformer was used to match the patch to a 50 ohm feed line. The efield and hfield generated by the patch antenna can be calculated by using a simulation tool such as cst microwave studio. A brief tutorial on microstrip antennas part 1 microwaves. This figure is usually an ellipse that has special cases. Using the microstrip patch antenna to feed the lens antenna is easy to implement due to its simple and compact size. Feed line radiation is isolated from patch radiation higher bandwidth is possible since probe inductance is eliminated allowing for a thick substrate, and also a doubleresonance can be created allows for use of different substrates to optimize antenna and feed circuit performance disadvantages. Proximity coupled patch antenna with microstrip feed 212 2.
Introduction to microstrip antennas university of houston. Mar 18, 2016 the tangential electric field at the main open aperture of the shorted patch can be considered as an equivalent magnetic current, while the two strips contribute two electric currents. Simulate and analyze a rectangular patch antenna using ansys hfss, including return loss and 3d radiation fields. Agilents ads eda tool is used for design and analysis of the antenna. As can be seen, a broad minimum of the crosspolarization pattern is attained at the. The electric field does not stop abruptly at the patch s periphery as in a cavity. Design of probe feed microstrip patch antenna in s band. The cp radiation in dualbands is a result of two multilayered truncated corner stacked square patches, while the reactive impedance surface ris is used for antenna size miniaturization for the lower operating frequency band. How is the magnetic field radiated in a microstrip patch. Readers may refer to balanis 1997 and carver and mink 1981 for some analytical modeling of a microstrip antenna. And because the loop antenna is somewhat the dual of the dipole as discussed earlier, the magnetic fields are strong in the near field of the loop antenna. Analysis and design of the rectangular microstrip patch antennas.
The bandwidth of the microstrip patch antenna can be improved by increasing the thickness of substrate or by decreasing its electric permittivity value. Near field focusing of rectangular microstrip patch. The acmsa uses an aperturecoupled line feed to excite a resonant patch element. So now there are eight ways to feed rf into a loop antenna. Design and performance analysis of inset feed microstrip square patch antenna for 2.
Lecture 5 fast and slow electric field antennas, field. Radiation pattern is the variation of the electric field as a function. These antennas have low radiation resistance and high reactance, so that their impedance is difficult to match to a transmitter. What ive just said applies to the farfield of the radiating em wave.
Aperture coupled circularly polarized microstrip patch antenna with single feed rainee n. Wideband rectangular microstrip patch antenna using l. To improve the antenna bandwidth, two of the patches are modified with truncated corners in the diagonal direction. It was decided to design a patch antenna from the theoretical study since it fulfils all the requirements for the antenna. The dimensions of antenna can be found in the hfss simulation file. Modern uwb antennas and equipment where cc and cd are expressed in terms of line width w, substrate thickness d, and relative permittivity. Microstrip antenna an overview sciencedirect topics. The instantaneous electric field vector traces a figure in time.
There are now eight ways to feed a magnetic or small loop. The polarisation of an antenna is determined by the wave radiated in a given direction that is identical to the direction of the electric field. The analysis of rectangular microstrip patch antenna rmpa operating on the tm0n0 modes is. Impedance matching between the feed and antenna patch is an important issue to obtain good return loss values. What ive just said applies to the far field of the radiating em wave. Antennas are used to receive and transmit electromagnetic energy.
It is dependent on the length l and width w of the patch as well as on the wavelength. Pdf effect of dielectric constant on the design of. Basically, the structure could be seen as a patch antenna electromagnetically coupled to the lshaped capacitively loaded monopole. Radiation pattern is the variation of the electric field as a function of angle and has two field. Note specifically the radiating electricfield configuration at each edge of the microstrip conductor. The large selfresonant loop antenna has a circumference close to one wavelength of the operating. Electric field from a microstrip patch antenna figure 3. Before studying patch antennas, lets digress for a while and talk about microstrip. However, application specific patch shapes are often used to optimize certain aspects of. The performance of microstrip patch antenna system depends on the. These field extensions are known as fringing fields and cause the patch to radiate. The proposed antenna is capable of receiving and transmitting signals at its operating range. Selecting best feeding technique of a rectangular patch. Hence, a substrate can enhance antennas radiation capability.
A planar quasimagneticelectric circularly polarized antenna. Besides, the lens antenna can be easily achieved high gain and low side lobes. In the antenna in figure 1, the center conductor of a coaxial line serves as the feed probe to couple electromagnetic energy in andor out of the patch. Several researchers are working to reduce the focused spot size and improve the power density within the focused region. These minima and maxima continuously change side like the phase of the rf signal. The receiving properties of antennas are characterized by the antenna affective area af,t,i, where the available power at the output of the receiving antenna prf is the product of the effective area of the receiving antenna in direction t,i and the flux density swm2hz1 incident from that direction. Generation of broadband highpurity dualmode oam beams.
The patch may be in a variety of shapes, but rectangular and circular are the most common. For this design, quarter wave transformer and inset fed rectangular microstrip patch antennas were used with an edge fed power feeding method. Note specifically the radiating electric field configuration at each edge of the microstrip conductor. As with any rf antenna, the feed impedance of a dipole antenna is dependent upon a variety of factors including the length, the feed position, the environment and the like. Hence, the fringing efields on the edge of the microstrip antenna add up in. Nakar follow this and additional works at the fsu digital library. First the model of the microstrip patch antenna has to be drawn in hfss. Miniaturized circularly polarized stacked patch antenna on. Keywordsmicrostrip patch antenna, frequency, gain, beamwidth,hfss,wireless communication. The patch cutout for the feed inset should be 2 times the microstrip width.
It consists of a planar dipole, a vertical quarter wavelength shorted patch, a. It consists of rectangular substrate and the metal trace layer as shown in fig. Increase in length of the microstrip patch probe feed microstrip antenna typically, to excite the fundamental tem mode, the length l of the rectangular patch. Hence, a substrate can enhance antenna s radiation capability. An electric field antenna that is not flush with the ground surface will distort the surrounding electric field.
Design and analysis of microstrip patch antenna arrays. A 44u microstrip patch antenna array has been proposed here to be. Matching reduces the loss of the signal and reflected power towards the transmission line that supplies a smooth transition of energy from the antenna input impedance to the feed line. Design of seriesfed bandwidthenhanced microstrip antenna. With a single feed, the proposed antenna exhibits an inherent phase difference of about 90 for the two kinds of currents, and therefore, a cp radiation is. Design of probe feed microstrip patch antenna in sband 419 figure 2. In radio engineering, an antenna is the interface between radio waves propagating through space and electric currents moving in metal conductors, used with a transmitter or receiver. This can in turn produce time varying electric field by faradays law and a propagating em field is created. Within this physical description there are two distinct antenna types. Some popular analytic modeling techniques for patch antennas are. Antenna,microstrip,patch antenna,coaxial cable,radio,microwave engineering,probe feed,cst,coaxia.
An antenna leadin is the transmission line, or feed line, which connects the antenna to a transmitter or receiver. If the path of the electric field vector follows a line, the antenna is said. This idea was first proposed in 1985 as a bandwidth enhancement technique 3. These magnetic fields ultimately give rise to the antenna radiation, and since they are somewhat immune to the human body, loop antennas tend to be much more robust in terms of performance when they are placed near a human. The tangential electric field at the main open aperture of the shorted patch can be considered as an equivalent magnetic current, while the two strips contribute two electric currents. Because the effective length of the microstrip conductor is a halfwavelength, the electric field is at maximum at the left and right edges due to the effective open circuit and the repeating field pattern at halfwavelength intervals. Its because its well understood that the magnetic part of an em field can be deduced from the electric field part and vice versa. Then, the recessed microstrip feeds for the other two patches are. Patch antenna is actually a patch antenna placed over a antenna base. Patch antenna construction the efield and hfield generated by the patch antenna can be calculated by using a simulation tool such as cst microwave studio. Values of the electric field strength in vm in free space location ex ey ez. Cross section of a patch antenna in its basic form a half wave long patch operates in what we call the fundamental mode. Here is the link page to the various patch antenna and microstrip antenna topics. A thicker substrate leads to a longer feed probe, a larger feed probe inductance and a degradation of impedance.
1204 1623 1573 797 1524 1441 487 950 12 623 1361 1399 263 146 845 265 1114 488 341 1132 213 315 1402 395 1493 680 604 251 726 667 1622 1377 518 1076 978 737 311 1208 632 460 871 1181