Search for answers or browse our Knowledge Base.
Guides | Models | Validation | Blog
-
Guides
-
-
- 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
- The Equivalent Circuit of a Balun
- AN-SOF Antenna Simulation Best Practices: Checking and Correcting Model Errors
-
-
- 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 ::
- Show All Articles (3) Collapse Articles
-
-
-
-
Models
-
- 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
-
- 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): A Compact Receiving Antenna with Directional Capabilities
- 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
-
- 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
-
-
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
-
Gain and VSWR of Helix in Axial Mode
This article is based on the geometric parameters for the helix defined in this link >.
A helical antenna operating in axial mode can be a highly directional radiator. Its radiation pattern consists of a main lobe and several secondary lobes, as Fig. 1 shows.
The gain increases as the number of turns increases for a certain range on the helix circumference, C/λ. Prof. Krauss has investigated this behavior and reported the measured data shown in Fig. 2, where the calculated results are also plotted. Refer to “Antennas” by John D. Krauss, 2nd Edition, McGraw-Hill, 1988.
Since the details about the experimental setup regarding the feeding system and wire radii involved has not been reported, we have varied the wire radius and the length of the short wire that connects the helix to the ground plane in order to obtain the closest fit for all curves at the same time. We can see that the agreement is quite good along most of the range of C/λ and that the gain maxima occurs around C/λ = 1.1 and 1.2 as Prof. Krauss has observed in his experiments.
Instead of reporting the measured input impedance in detail, the VSWR has been published in Fig. 7-23 of Prof. Krauss book. These data are reproduced in Fig. 3 and compared with the calculated results, where the VSWR is shown as a function of the normalized helix circumference for a 6-turn, 14° helical antenna. We can see that the agreement between the measured and computed results is quite good and that the simulation can reproduce the dip at C/λ = 0.65 as well as the peak structure between 1.2 and 1.5.