Modeling a Super J-Pole: A Look Inside a 5-Element Collinear Antenna

Simulating a Super J-Pole: A 2m Antenna Analysis. This article describes a 5-element collinear antenna design for the 2m band, its radiation pattern, VSWR, and key components for optimal performance.

High-Performance Omnidirectional Antenna Design

The collinear J-Pole, also known as the Super J-Pole, offers significant performance improvements over a standard J-Pole antenna. This design boasts increased gain and improved self-resonance due to its unique feeding mechanism at the “J” section.

Technical Specifications

The Super J-Pole features five collinear radiating elements connected by phasing coils. Each linear element is a half-wavelength long, ensuring optimal performance at the target frequency. The phasing coils themselves are strategically designed with a length of one-quarter wavelength.

Convenient Feed Point and Impedance Matching

The feed point is conveniently located at the base of the antenna on a J-dipole. By carefully adjusting the position of the feed point along the J section, the Voltage Standing Wave Ratio (VSWR) can be minimized, eliminating the need for an external impedance matching network. This feature simplifies antenna construction and deployment.

Top Termination and Overall Dimensions

A small loop at the top end of the antenna serves as a tie point, measuring a mere 1/2 inch in diameter. The total length of the antenna is approximately 295 inches. Each phasing coil features 32 turns and has a diameter of 5/8 inches.

Detailed Antenna Model in AN-SOF

The figure accompanying this article showcases the antenna model within the AN-SOF workspace on the left. Additionally, the calculated radiation pattern (gain in dBi) is displayed on the right, along with the VSWR curve at the bottom right corner. To provide a closer look at the intricate details, the model includes zoomed-in views of a single coil, the top tie loop, and the feed point at the J section.

Importance of Accurate Coil Modeling

Accurate modeling of the phasing coils is crucial for optimizing the Super J-Pole’s performance. Simulation software capable of handling curved wire segments and closely spaced elements is essential. AN-SOF offers the ideal solution with its Helix wire function, enabling the creation of a highly accurate model for each coil using a single segment per turn. This exemplifies the software’s efficiency in simulating complex antenna designs.

See Also:

The 5-in-1 J-Pole Antenna Solution for Multiband Communications