Thank you to Antenom Antenna Technologies for submitting news about the upcoming crowdfunding campaign for their "NanoFarfield" antenna far field measurement system.
When building and measuring antennas, most people stop at measuring VSWR. However, VSWR is only a small part of the picture for antenna performance. The antenna's far-field pattern determines its gain in a particular direction. Measuring this is typically difficult as it requires a signal source, hiring and travelling to an expensive anechoic chamber, and some sort of automated system to rotate the antenna 360 degrees.
In recent posts, we've seen low-cost DIY solutions explored that use a NanoVNA or RTL-SDR to measure an antenna in an open field (to avoid multipath reflections like an anechoic chamber would) at various points, and then charting the results. However, this is a slow, manual process and requires purchasing and setting up various individual components.
NanoFarfield productizes the low-cost approach, providing a portable measurement system that can be brought into an open environment. The measurement process is automated, by using a motorized rotator which spins the antenna under test 360 degrees in front of a directional signal source. The team write:
As many SDR users know, building antennas is relatively easy, but measuring the actual radiation pattern is often difficult. Normally this requires an anechoic chamber or a large outdoor antenna range, which is usually inaccessible to hobbyists, students, and small labs.
We have been working on a portable antenna measurement system called NanoFarField, designed to measure antenna radiation patterns outside the lab using commonly available VNAs such as NanoVNA or LiteVNA.
Instead of requiring a full antenna range facility, the system allows users to perform radiation pattern measurements in open environments using a compact rotating platform and VNA-based S21 measurements. The goal is to make antenna pattern measurement accessible to:
• SDR and ham radio experimenters
• antenna designers and RF engineers
• universities and student labs
• field testing scenarios
The system effectively acts as a portable antenna range that can fit into a backpack.
Typical workflow:
The antenna under test is placed on the rotating platform.
A reference antenna is positioned at a fixed distance.
The NanoVNA / LiteVNA performs S21 measurements while the antenna rotates.
Software reconstructs the radiation pattern from the measurement data.
This allows users to measure:
• azimuth radiation patterns
• antenna directivity trends
• relative gain patterns
• beamwidth and nulls
without requiring an expensive measurement facility.
Because many SDR enthusiasts design and build their own antennas, we thought this tool could be useful for the community as a low-cost method to visualize antenna performance.
The frequency range is specified at 50 - 6000 MHz, with a typical angular resolution of 1 degrees, and it includes a wideband amplifier to improve results. The hardware is provided as open source, however, the software will be closed source, and provided as a Windows executable.
