Temperature-Compensated Microstrip Antenna for Ice Measurement and Wireless Sensor Networ

The primary goal of this thesis is to devise and develop a technique of temperature compensation related to the resonant frequency of a microstrip patch antenna (MPA). Such a temperaturecompensated microstrip patch antenna capable of standing against a substantial variation of temperature is exploited as part of an ice-sensor for measuring ice loading thickness. Microstrip antennas designed in this way are used in a wireless temperature sensor network in connection with its critical applications of a helicopter de-icing system. A prototype of wireless temperature sensor network which remotely controls turning-on or turning-off heaters intended for de-icing is developed. Among all other antennas, the microstrip antenna is selected due to its versatility. Thanks to the susceptibility of the microstrip patch antenna to external factors, such as temperature fluctuations, its resonant frequency suffers from a stability issue. In addition to that, its resonance causing a narrow frequency bandwidth does not lead to a straightforwardly preferred solution. To minimize the temperature-induced frequency instability and also to prevent losing signal or interferences from adjacent channels, one needs to develop a very efficient and practical temperature compensation technique.;In this work, an efficient and practical technique through a resonant frequency temperature compensation for microstrip patch antennas is devised, which is superior to existing counterparts both in its simplicity and frequency stability. To the best of the author`s knowledge, nothing similar was done before.;For the first time, a temperature dependence of microstrip antenna resonant frequency is investigated through a mathematical formulation of frequency drift for rectangular, circular, and triangular patch geometries. The circuit model for analyzing temperature impact on microstrip antenna resonant frequency suitable for computer-aided design (CAD) procedures is adopted. Electromagnetic simulations along with results of the adopted circuit model support the derived theory. Results of temperature impact on the frequency drift of microstrip antennas resonant at 2.4 GHz modelled on different substrates are shown and compared. Analysis, simulation, and experimental results show that antennas built on thicker substrates exhibit a better temperature behaviour of the resonant frequency.