This master’s thesis describes the design, implementation and testing of an active antenna intended for use with global navigation satellite systems. The active antenna is composed of two major parts, a dual-band circular patch antenna and a dual-band low-noise amplifier. To streamline the design process, a modular solution was adopted. This enabled the functionality of every part in the signal path to be verified before the final active antenna was designed. A practical method to develop dual-band stacked circular patch antennas, along with a systematic way to tune the resonant frequencies and impedance of the antenna, is also presented. Testing of the antenna in realistic scenarios shows that the active antenna performs as expected and predicted by simulations. / <p>Examensarbetet är utfört vid Institutionen för teknik och naturvetenskap (ITN) vid Tekniska fakulteten, Linköpings universitet</p>

The project is aimed to design an antenna array for an aircraft positioning system at an airport. The system operates at frequencies 1030 MHz and 1090 MHz. The antenna is also used by the DME/TACAN system operating in frequency range from 1025 MHz to 1150 MHz. The required impedance bandwidth of the antenna array is 125 MHz, i.ee from 1025 MHz to 1150 MHz. The theoretical part of the thesis analyses properties of different patch antennas and discusses the possibility of extending the impedance bandwidth. The practical part is focused on the development of the numerical model of the broadband stacked patch antennas. In addition, properties of the 3-element and 4-element antenna array are compared. At the end, results of the thesis are summarized.