Antenna tuning unit

摘要

A system, apparatus, and method directed to impedance matching an antenna with a transmitter for non-directional radio beacons. The apparatus includes an L-type impedance network comprising non-capacitive elements and at least one variable inductor on each branch of the impedance network. Also, system, apparatus, and method directed to providing a low power signal for tuning the antenna. The apparatus includes an impedance matching network and a signal generator. Also, a system, apparatus, and method directed to providing an estimate of near-field strength of a signal from an antenna. The apparatus includes an impedance matching network, a near-field signal strength detector, and microcontroller configured to estimate the near-field signal strength. Corresponding systems includes using the respective apparatuses between an antenna and a transmitter. Corresponding methods are directed to the use of the apparatuses and systems.

主权项

1. An apparatus for tuning an electrically short, navigational beacon antenna adapted for use with a radio transmitter and an electrical ground, the apparatus comprising:
an impedance matching network comprising: a first end configured to be in electrical communication with the radio transmitter, the radio transmitter generating a medium or high power signal between 190 kHz and 1800 kHz with a wavelength about ten times or greater than a longest dimension of the electrically short, navigational beacon antenna; a second end configured to be in electrical communication with the electrically short, navigational beacon antenna; a first impedance element electrically connected between the first end and the second end; and a second impedance element electrically connected between the first end and the electrical ground; wherein each of the impedance elements comprises an air core variable inductor and wherein each of the impedance elements only comprise non-capacitive circuit components.