Inbuilt Miniature Inline VSWR Meter and Antenna Analyser for Handheld Radio Transceivers

Abstract

This paper discusses an inbuilt miniature inline voltage standing wave ratio (VSWR) meter and antenna analyser for handheld radio transceivers. Most high-end and special purpose handheld radios include a VSWR meter inside that measures the antenna parameters all the time while transmitting. Such a feature helps mitigate inadequate antennas, loss of power and sensitivity, overload of the final stage of the transmitter, excessive heat dissipation and battery energy wasting. Most such meters measure VSWR only and knowledge of this parameter is sufficient in most scenarios. The current article presents a simple to build, high efficiency and compact, yet sophisticated computer controlled VSWR meter that also measures other parameters of the antenna besides the VSWR. The meter capabilities are equal to or better than professional or specialized antenna analysers while being extremely small in size and low in complexity. The proposed device is capable of measuring complex antenna impedance and additionally revealing the value and sign of the antenna reactance, i.e. whether it is capacitive or inductive.