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Guides


 Complete Workflow: Modeling, Feeding, and Tuning a 20m Band Dipole Antenna
 DIY Helix High Gain Directional Antenna: From Simulation to 3D Printing
 Evaluating EMF Compliance  Part 1: A Guide to FarField RF Exposure Assessments
 Design Guidelines for Skeleton Slot Antennas: A SimulationDriven Approach
 Simplified Modeling for Microstrip Antennas on Ungrounded Dielectric Substrates: Accuracy Meets Simplicity
 Fast Modeling of a Monopole Supported by a Broadcast Tower
 Linking LogPeriodic Antenna Elements Using Transmission Lines
 Wave Matching Coefficient: Defining the Practical NearFar Field Boundary
 ANSOF Mastery: Adding Elevated Radials Quickly
 Enhancing Antenna Design: Project Merging in ANSOF
 On the Modeling of Radio Masts
 The Equivalent Circuit of a Balun
 ANSOF Antenna Simulation Best Practices: Checking and Correcting Model Errors


 ANSOF 9: Taking Antenna Design Further with New Feeder and Tuner Calculators
 ANSOF Antenna Simulation Software  Version 8.90 Release Notes
 ANSOF 8.70: Enhancing Your Antenna Design Journey
 Introducing ANSOF 8.50: Enhanced Antenna Design & Simulation Software
 Get Ready for the Next Level of Antenna Design: ANSOF 8.50 is Coming Soon!
 Explore the CuttingEdge World of ANSOF Antenna Simulation Software!
 Upgrade to ANSOF 8.20  Unleash Your Potential
 ANSOF 8: Elevating Antenna Simulation to the Next Level
 New Release: ANSOF 7.90
 ANSOF 7.80 is ready!
 New ANSOF User Guide
 New Release: ANSOF 7.50
 ANSOF 7.20 is ready!
 New Release :: ANSOF 7.10 ::
 ANSOF 7.0 is Here!
 New Release :: ANSOF 6.40 ::
 New Release :: ANSOF 6.20 ::
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Models

 Modeling a Super JPole: A Look Inside a 5Element Collinear Antenna
 Simulating the Ingenious Multiband Omnidirectional Dipole Antenna Design
 The Loop on Ground (LoG): A Compact Receiving Antenna with Directional Capabilities
 Precision Simulations with ANSOF for Magnetic Loop Antennas
 Advantages of ANSOF for Simulating 433 MHz Spring Helical Antennas for ISM & LoRa Applications
 Radio Mast Above Wire Screen
 Square Loop Antenna
 Receiving Loop Antenna
 Monopole Above Earth Ground
 TopLoaded Short Monopole
 HalfWave Dipole
 Folded Dipole
 Dipole Antenna
 The 5in1 JPole Antenna Solution for Multiband Communications

 Extended Double Zepp (EDZ): A Phased Array Solution for Directional Antenna Applications
 Transmission Line Feeding for Antennas: The FourSquare Array
 LogPeriodic Christmas Tree
 Enhancing VHF Performance: The Dual Reflector Moxon Antenna for 145 MHz
 Building a Compact HighPerformance UHF Array with ANSOF: A 4Element Biquad Design
 Building a Beam: Modeling a 5Element 2m Band Quad Array
 Broadside Dipole Array
 LogPeriodic Dipole Array
 Broadband Directional Antenna
 A Closer Look at the HF Skeleton Slot Antenna
 The 17m Band 2Element Delta Loop Beam: A Compact, HighGain Antenna for DX Enthusiasts
 Enhancing Satellite Links: The MoxonYagi Dual Band VHF/UHF Antenna

Validation


 Simple Dual Band Vertical Dipole for the 2m and 70cm Bands
 Linear Antenna Theory: Historical Approximations and Numerical Validation
 Validating Panel RBS Antenna with Dipole Radiators against IEC 62232
 Directivity of V Antennas
 Enhanced Methodology for Monopoles Above Radial Wire Ground Screens
 Dipole Gain and Radiation Resistance
 Convergence of the Dipole Input Impedance
 Impedance of Cylindrical Antennas

A Transmission Line
Twowire transmission lines can be modeled explicitly in ANSOF. In this example, the line will have a single wire but there will be a ground plane below it, so we have the mirror image of the wire as the return of the line.
Step 1  Setup
Go to the Setup tab and select Single in the Frequency panel >. Set a frequency of 100 MHz. Then, go to the Environment panel > and set a perfect ground plane at Z = 0, Fig. 1.
Step 2  Draw
Go to the Workspace tab, right click on the screen, and select Line from the popup menu >. Draw a horizontal line with the coordinates indicated in Fig. 2. Next, connect the ends of the line to the ground plane by drawing two vertical wires. You can right click on the line and select the commands Start point to GND and End point to GND to connect the ends to ground.
Set 40 segments for the horizontal wire and 1 segment for each of the vertical wires. Note that dimensions in Fig. 1 are in millimeters. To change the unit of length, go to Tools menu > Preferences > Units tab >.
Right click on the vertical wire at (0,0,0), select Source/Load from the displayed popup menu and put a 1 Volt voltage source on it. Refer to Adding Sources > to add the voltage source.
Step 3  Run
Go to the Run menu and click on Run Currents. Since we are only interested in the current distribution and the input impedance, it is not necessary to calculate the radiated field (you can do it to check that it is practically negligible). Click on the Zin (List Input Impedances) button on the toolbar to display a table where the input impedance is shown as a function of frequency, Fig. 3. Refer to Listing Input Impedances >.
The impedance obtained is practically reactive, j512 Ohm. The small real part is the radiation resistance, since the line radiates a small amount of power, which is negligible but not zero.
This is a shortcircuited line. Now right click on the vertical wire at (0,500,0) mm and select Delete from the popup menu to remove it. You will get an opencircuited line in this way. Rerun the calculations with the Run Currents command in the Run menu. The input impedance will now be j105 Ohm.
Summarizing, we have,
 Z_{in} (shortcircuited line) = j512 Ohm.
 Z_{in} (opencircuited line) = j105 Ohm.
According to transmission line theory, the characteristic impedance can be calculated as the geometric mean of the shortcircuit and opencircuit line input impedances, hence
On the other hand, the expression for the characteristic impedance of a line above a ground plane is given by:
where a is the wire crosssection radius and h is the line height above the ground plane. As we can see, the agreement between the characteristic impedance obtained from ANSOF and that from theory is quite good. The difference is since the theory neglects the radiation of the line, and the logarithmic formula is an approximation that is valid when h >> a.