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Guides
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- Modeling Common-Mode Currents in Coaxial Cables: A Hybrid Approach
- Evaluating EMF Compliance - Part 2: Using Near-Field Calculations to Determine Exclusion Zones
- Beyond Analytical Formulas: Accurate Coil Inductance Calculation with AN-SOF
- 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 Far-Field RF Exposure Assessments
- Design Guidelines for Skeleton Slot Antennas: A Simulation-Driven Approach
- Simplified Modeling for Microstrip Antennas on Ungrounded Dielectric Substrates: Accuracy Meets Simplicity
- Fast Modeling of a Monopole Supported by a Broadcast Tower
- Linking Log-Periodic Antenna Elements Using Transmission Lines
- Wave Matching Coefficient: Defining the Practical Near-Far Field Boundary
- AN-SOF Mastery: Adding Elevated Radials Quickly
- Enhancing Antenna Design: Project Merging in AN-SOF
- On the Modeling of Radio Masts
- RF Techniques: Implicit Modeling and Equivalent Circuits for Baluns
- AN-SOF Antenna Simulation Best Practices: Checking and Correcting Model Errors
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- AN-SOF 9.50 Release: Streamlining Polarization, Geometry, and EMF Calculations
- AN-SOF 9: Taking Antenna Design Further with New Feeder and Tuner Calculators
- AN-SOF Antenna Simulation Software - Version 8.90 Release Notes
- AN-SOF 8.70: Enhancing Your Antenna Design Journey
- Introducing AN-SOF 8.50: Enhanced Antenna Design & Simulation Software
- Get Ready for the Next Level of Antenna Design: AN-SOF 8.50 is Coming Soon!
- Explore the Cutting-Edge World of AN-SOF Antenna Simulation Software!
- Upgrade to AN-SOF 8.20 - Unleash Your Potential
- AN-SOF 8: Elevating Antenna Simulation to the Next Level
- New Release: AN-SOF 7.90
- AN-SOF 7.80 is ready!
- New AN-SOF User Guide
- New Release: AN-SOF 7.50
- AN-SOF 7.20 is ready!
- New Release :: AN-SOF 7.10 ::
- AN-SOF 7.0 is Here!
- New Release :: AN-SOF 6.40 ::
- New Release :: AN-SOF 6.20 ::
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Models
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- Download Examples
- Modeling a Center-Fed Cylindrical Antenna with AN-SOF
- Yagi-Uda Array
- Monopole Over Real Ground
- Helix Antenna in Axial Mode
- Modeling a Circular Loop Antenna in AN-SOF: A Step-by-Step Guide
- A Transmission Line
- An RLC Circuit
- Explore 5 Antenna Models with Less Than 50 Segments in AN-SOF Trial Version
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- Modeling a Super J-Pole: A Look Inside a 5-Element Collinear Antenna
- Simulating the Ingenious Multiband Omnidirectional Dipole Antenna Design
- The Loop on Ground (LoG) Antenna: A Compact Solution for Directional Reception
- Precision Simulations with AN-SOF for Magnetic Loop Antennas
- Advantages of AN-SOF 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
- Top-Loaded Short Monopole
- Half-Wave Dipole
- Folded Dipole
- Dipole Antenna
- The 5-in-1 J-Pole Antenna Solution for Multiband Communications
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- The Lazy-H Antenna: A 10-Meter Band Design Guide
- Extended Double Zepp (EDZ): A Phased Array Solution for Directional Antenna Applications
- Transmission Line Feeding for Antennas: The Four-Square Array
- Log-Periodic Christmas Tree
- Enhancing VHF Performance: The Dual Reflector Moxon Antenna for 145 MHz
- Building a Compact High-Performance UHF Array with AN-SOF: A 4-Element Biquad Design
- Building a Beam: Modeling a 5-Element 2m Band Quad Array
- Broadside Dipole Array
- Log-Periodic Dipole Array
- Broadband Directional Antenna
- A Closer Look at the HF Skeleton Slot Antenna
- The 17m Band 2-Element Delta Loop Beam: A Compact, High-Gain Antenna for DX Enthusiasts
- Enhancing Satellite Links: The Moxon-Yagi Dual Band VHF/UHF Antenna
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Validation
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- 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
- Validating V Antennas: Directivity Analysis with AN-SOF
- Enhanced Methodology for Monopoles Above Radial Wire Ground Screens
- Dipole Gain and Radiation Resistance
- Convergence of the Dipole Input Impedance
- Validating Dipole Antenna Simulations: A Comparative Study with King-Middleton
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Logarithmic Spiral
The Logarithmic Spiral refers to a spiral with polar equation r(α) = r0 exp(bα), where r0 is the starting radius (r at α = 0), b = p/(2πr0) and p is the starting pitch, that is, the derivative 2πdr/dα at α = 0 (starting growth rate of the spiral radius r(α) per turn). The first two terms of the Taylor expansion r(α) = r0 + p/(2π) α + r0(bα)2/2 + … give the polar equation of an Archimedean spiral.
Go to Draw > Logarithmic Spiral in the main menu to display the Draw dialog box for the Logarithmic Spiral. This dialog box has three pages: Logarithmic Spiral, Attributes, and Materials.
The Logarithmic Spiral page
In the Logarithmic Spiral page, the geometrical parameters for the Logarithmic Spiral can be set, Fig. 1.
The logarithmic spiral is entered by giving the Start Point, Start Radius r0, Start Pitch p (positive or negative) and Number of Turns (complete turns and fractions of a turn can be defined). The spiral lies on a plane given by the Orientation Angles Theta and Phi (normal to the plane in spherical coordinates) and can be rotated by setting a Rotation Angle, Fig. 2.
Once the geometrical parameters in the Logarithmic Spiral page have been set, the Attributes > page can be selected, where the number of segments and cross-section can be set. The wire resistivity and coating can be set in the Materials > page.