Nov 01, 2015 4nec2 antenna modeling of near field antenna interaction scenario based on video by michael pfeiffer no7on s. Input impedance for different antenna heights 29 9. This section investigates simulation of the rectangular probefed. This results in zero radiation at certain angles where the radio waves from the different parts arrive out of phase, and local maxima of radiation at other angles. Optimizing the antenna length thick wire dipole of chapter 7 27 9. Modern uwb antennas and equipment where cc and cd are expressed in terms of line width w, substrate thickness d, and relative permittivity. Is there any free software where i can design a microstrip patch. Intel cpu is required on xp and vista systems but not on windows 7 and later. Design and implementation of patch antenna 5 designs, and very versatile in terms of resonant frequency, polarization, pattern, and impedance.
It consists of a flat rectangular sheet or patch of metal, mounted over a larger sheet of metal called a ground plane. Nec 2 does not allow to model underground wires ref. Marquette university, 2011 microstrip antennas are a type of printed antenna which consists of a patch on top of a grounded substrate. The size of the radiation pattern can be adjusted with the zoom. May 03, 2015 a simple antenna nec2 was based on punch cards and an antenna model was described as a series of cards. Pdf micro strip patch antenna and its applications.
This paperdeals with the problem of size and performance of antenna. By using a feeding structure composed of a stepshaped feeding strip in the air substrate and a coplanar strip in the narrow radiating patch, the proposed antenna can reduce cross. Moreover, by holding them in an upright position and arranging them like checkered plates, nec has formed flow paths for the air containing heat and realized heat dissipation from the antenna surface. Nec 2 retains all features of the earlier version nec 1 except for a restart option. Polarization is at right angles to the length of the slots, parallel to the feedline orientation shown in fig. This rectangular microstrip patch antenna is designed for wireless communication application that works at 2. The nec ground plane gn card is always at the origin z 0. This paper presents design and simulation of a square micro strip patch antenna at 2.
Simulate and analyze a rectangular patch antenna using ansys hfss, including return loss and 3d radiation fields. Results the designed microstrip patch antenna with four slits and a pair of truncated corners are simulated using cadfeko for finding the electric far field radiation, gain, directivity, radiation. Figure 2 from design a square microstrip patch antenna for. The paper presents a broadband microstrip patch antenna for wireless. Microstrip patch antennas or simply patch antenna are increasingly useful because the antenna is printed directly onto a circuit board. To install the 4nec2 package, follow the below steps.
Planar antennas such as microstrip platepatch antennas have attracted many. A variety of realizations yield f 1 f 2 ratios ranging from 1. The following files and links point to nec aoyo models of various ham antennas that i have simulated andor tested over the past 30 years as an antenna designer. If the antenna is excited at a resonance frequency, a strong field is set up inside the cavity, and a strong current on the bottom surface of the patch. Generally, patch antenna has a shape of rectangle, and it can be feed with copper cable. Figure 1 topview of the patch and side view of whole antenna structure.
Defaults the user only needs the intended operating frequency here. Nec numerical electric code is a simulation method for wire antennas developed by the. These results show that a microstrip patch antenna mainly radiates in the vertical direction. In all the radiation patterns calculated with nec 2, the gain is expressed in dbi. These antennas can be mounted on the surface of highperformance aircraft, spacecraft, satellites, missiles, cars, and even handheld mobile telephones. How to start modeling antennas using eznec greg ordy, w8wwv ctu, contest university dayton, may 19, 2011 version 1. Open end extension like the open end of a microstrip line.
Nec develops antenna heat dissipation technology enabling. Nec numerical electric code is a simulation method for wire antennas, developed by the lawrence livermore laboratory in 1981 or the navy. Thus, the patch operates as an array of two slots with a freespace separation somewhat less than. It is built around the numerical solution of integral equations for the currents induced on the structure by sources or incident fields. Results the designed microstrip patch antenna with four slits and a pair of truncated corners are simulated using cadfeko for finding the electric far field radiation, gain, directivity, radiation pattern e. Note that,in order to draw a true 3d radiation pattern, the antenna must be arranged as to have the feed point just in 0,0,0 coordinates. 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. They look pretty weird, as can be seen in the following photo. The jpole antenna is a common omni directional antenna used in amateur radio, particularly on the vhf and uhf bands. It also has a wide angle of beam in its radiation pattern. The utility nec2 for mmana is intended for calculation of antenna models made and optimized in program mmana. The radiating edges of a patch can be seen as two radiating slots placed above a ground plane and, assuming all radiation occurs in one half of the hemisphere on the patch side of the ground, we get a 3 db directivity increase.
Lower medium parameters are as specified for the second medium on the gn card or on the gd card. Half of this antenna is 58 wave and is a common length for 2m mobile antennas. An nec2 compatible numerical electromagnetics code by. Ive downloaded qantenna and 4nec2 to try and model my antenna and see what i can do, however neither of these programs allow you to make an antenna as far as i can tell they require you to. Thanks for downloading and reading this definitive guide to the widely popular 4nec2 antenna modeling software. Microstrip antenna an overview sciencedirect topics. Technical reports from the electronics group at the. The nec engine provides support for modeling patch antennas as well.
This radiation pattern shows that the antenna radiates more power in a certain direction than another direction. Maximum radiation is normal to the plane of the patch. Lower medium parameters are as specified for the second medium on the gn cart or on the gd card. The distance between the two is extremely critical and it is important that you can easily vary the gap to find the sweet spot where you get the desired antenna pattern. Notice that the radiation resistance impedance is about 90 ohms. This means that most the incident power transfer to the square patch making the antenna radiates efficiently. Nec visualization, optimization and sweeping tool the 4nec2 tool is a windows and nec 2 or nec 4 based tool for both the starting and experienced antenna modeler that can be used to create, view and check your antenna geometry structure and generate, display and compare near and farfield radiation. The coaxial feed or probe feed is a very common technique used for.
Nec based antenna modeler and optimizer by arie voors 4nec2 is a completely free nec2, nec4 and windows based tool for creating, viewing, optimizing and checking 2d and 3d style antenna geometry structures and generate, display andor compare near farfield radiation patterns for both the starting and experienced antenna modeler. The basics of patch antennas, updated orban microwave. The picture to the right is of a 2m amateur radio band jpole i built from an eznec simulation. There is a wide and varied market of applications that embed the nec2 code within. Nec2 nec2 is a highly capable version of the code which is in the public domain. Radiation pattern the patchs radiation at the fringing fields results in a certain far field radiation pattern. Therefore, they do not contribute to the radiation of the antenna ref. An antenna radiation pattern or antenna pattern is defined as a mathematical function or a graphical representation of the radiation properties of the antenna as a function of space coordinates.
If the antenna had a 100% radiation efficiency, all directivity would be converted to gain. A patch antenna is a type of radio antenna with a low profile, which can be mounted on a flat surface. Nec code and experiments in the rf laboratory were used for this airspaced patch. This antenna can be matched to 50 ohms by using a series inductor. Antenna modeling links, stealth antennas, lpcad, aprs. Nec 2 is not adequate to model small size loop antennas perimeter lower than 0. Calculation is made with use of nec 2, including calculations above a surface of the ground in sommerfeldnorton model, calculations with use nec 2 extended thin wire kernel ethwk and voltage excitations by current slope discontinuity voltage sources csdvs.
Supernec model structure of investigated patch antennas. Typical half wave patches have efficiencies well above 90%. Major additions in nec 2 are the numerical greens function for partitionedmatrix solution and a treatment for lossy grounds that is accurate for antennas very close to the ground surface. Xls allow you to automate most of the common tasks associated with using a nec 2 engine for modelling antennas. Nec is a completely free software for wire and surface antennas based on method of moments. An advantage of the patch antenna is their affiliation to the family of the planar array antennas. Figure 3 and figure 4 show the radiation patterns in the eplane and hplane of the designed antenna at 2. Nec visualization, optimization and sweeping tool the 4nec2 tool is a windows and nec2 or nec4 based tool for both the starting and experienced antenna modeler that can be used to create, view and check your antenna geometry structure and generate, display and compare near and farfield radiation patterns. The microstrip antenna s radiation arises from the fringing fields, which are due to the advantageous voltage distribution. Basics of antennas giant metrewave radio telescope.
How to produce a nec antenna file and what software to use. Figure 2 present the simulated 2d cut view and 3d far zone eplane radiation patterns for this antenna. The square micro strip patch antenna was analyzed using ansoftansys hfss. We used a tool nec numerical electromagnetic code to model antenna on. So im really trying to get to grips with antenna radiation patterns, and more importantly things that are to close to the antenna that might interfere. Nec2 is a highly capable version of the code which is in the public domain. Analysis of an airspaced patch antenna near 1800 mhz.
The numerical electromagnetics code nec2 is a useroriented computer code for analysis of the electromagnetic response of antennas and other metal structures. For a rectangular microstrip patch antenna, the resonance frequency for any tm mn mode is. Some common antenna radiation patterns february 11, 2012 antennas antenna, coverage, radiation pattern john ya a radiation pattern is a 3 dimensional description of how an antenna radiates power in the surrounding space. The results obtain that microstrip patch antenna can be used as client antenna in computer and workable antenna for wireless fidelity. It was originally written in fortran in the 1970s by gerald burke and andrew poggio of the lawrence livermore national laboratory. Click on the image to the left to see a screen shot from eznec v. Normal radiation pattern for patch antenna 1 the strict definition of directivity is the amount of power in a particular direction as a fraction of the total average power radiated by a similar antenna that radiates equally in all directions. Analysis of an airspaced patch antenna near 1800 mhz hermine n. The nec files may be used with any of the nec 2 or nec 4 programs such as 4nec2, gnec or cocoanec, however some of them with tapered elements may only be simulated accurately by nec 4. 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. Apr 12, 2014 this is a three dimensional plot of the current distribution and radiation pattern of a horizontallypolarized 5element cubical quad antenna for 432 mhz at 1.
The patch antenna is therefore a voltage radiator, as opposed to the wire antennas, which radiate because the currents add up in phase and are therefore. What do hobbyists use if they have a desireneed to simulate a pcb antenna. To realize this an antenna is divided into short segments with linear variation of current and voltage like spice when simulating circuits. Using two completely identically manu factured patch antennas with a resonant frequency of 2. Jul 25, 2018 air spaced patch antenna radiation pattern you could use the free asap simulation program, which handles thin dielectrics, you could shell out a few hundred dollars for a copy of nec4, you could buy gemacs if you live in the usa, or you could add distributed capacitors to a nec2 model with ld cards hook up one capacitor in the middle of each. They are the original type of microstrip antenna described by howell in 1972. Measurement of a circularly polarized patch antenna at 1. The fundamentals of patch antenna design and performance. Therefore for training a simple 6 turns antenna is calculated, see fig 1. This is a 3 rd party book and is not connected to arie in any way. Shevgaonkar, dept of electrical engineering, iit bombay. I used computer software 4nec2 antenna modeler and optimizer version 5. Well model a vertical monopole like a whip antenna on an old radio.
Patch antenna design gareth louis shaw a dissertation submitted to the faculty of engineering and the built environment, university of the witwatersrand, johannesburg, in ful. The proposed microstrip patch antenna achieves a fractional bandwidth of 21. It also includes stateoftheart 3d visualization and a drawing style structure editor. The loads and transmission lines used in nec2 are mathematical models instead of physical models. The 58 wave antenna is typically fed against a ground plane car roof and is usually matched with a tapped inductor. A novel technique for enhancing bandwidth and gain of microstrip patch antenna is successfully designed in this pa per. Radiation pattern of the microstrip patch antenna figure 3.
Find the range where the radiation pattern looks pleasing with a well defined rounded main lobe and the gain is reasonable and go for the middle. Read 36947 times 0 members and 1 guest are viewing this topic. The numerical electromagnetics code, or nec, is a popular antenna modeling system for wire. Take into account that nec 2 computes the total current in the antenna, without making differences between common mode currents and differential mode currents ref.
Antenna simulations with 4nec2 including an application example. A major limitation for the performance of the patch antenna is the dielectric substrate. Listed under the software antenna analysis category that is. In most antennas, the radiation from the different parts of the antenna interferes at some angles. Square patch antenna for breast cancer diagnosis at 2. Far field pattern for different antenna heights 31 10.
This produces significant radiation a good antenna. With a patch antenna, varying the height by only one millimeter, has a large effect on the pattern. Typical gain of a patch antenna will be greater than 1. The numerical electromagnetics code, or nec, is a popular antenna modeling system for wire and surface antennas. This is in agreement with the theoretical radiation. If i is the current flowing through the antenna at its terminals then we. Also, this provides around 30 mhz bandwidth at the operating frequency.
Jul, 2014 introduction this is basic instructions for handmade 2300 mhz 14dbi double biquad external antenna. The real part is responsible for radiation and power loss. Therefore, nec has used antennas with a splitring structure note 1, to achieve about half the size of a general patch antenna. It is restricted to antenna elements of a single diameter although some software providers have introduced corrections for linear elements whose diameters varies. The distinctive feature of these antennas is their ease of construction. The standard is nec2 there are many software applicati ons, even free ones. A patch microstrip antenna with an inverted v ground plane capable of improving radiation performance for a wireless local area network wlan access point in the 2. This makes it hard but not impossible for a radio amateur to experiment with printed circuit board patch antennas and micro strip lines. Additional benefits of patch antennas is that they are easily fabricated making them cost effective.