VHF/UHF Antenna Measurements Based on Multi Probe Array Technology

Accurately measuring the radiation characteristics of electrically small antennas, particularly those with low directivity, presents a challenge due to the inevitable coupling between the antenna, the measurement chamber, and the associated equipment. This challenge becomes even more pronounced when dealing with antennas operating at frequencies in the VHF/UHF range, which introduces complexity to the measurement instrumentation, testing chamber, and the absorbing materials used. Spherical Near Field (SNF) testing techniques are widely recognized as the most precise and suitable methods for such measurements, primarily because they allow for the overall system dimensions to be minimized. The application of a multi-probe acquisition further enhances the compactness and efficiency of these measurement setups. This paper provides an in-depth investigation of measurement accuracy for low-directivity antennas at VHF/UHF frequencies using multi-probe systems. Specifically, the main errors contributions affecting the measurement uncertainty of the radiation pattern and gain are discussed and analyzed.