Integrated Microstrip Patch Antenna and Lna Assembly for Gps Repeaters

Global Positioning System (GPS), is a space-based radio navigation system, consisting of 24 satellites and ground support. GPS provides users with accurate information about their position and velocity, as well as the time, anywhere in the world and in all weather conditions. GPS was initiated in 1973. It is now the heart of modern day navigation systems. GPS became attractive to a broad spectrum of users, as its capabilities are accessible using small, inexpensive equipment. There is a little problem with GPS system that it has a poor reception inside the buildings and other covered structures. As GPS is becoming a part of daily life there is a requirement that user should access GPS inside the buildings and covered structures. To meet these requirements GPS repeaters are used. The main purpose of a GPS repeater is to pickup signal from the satellite and after amplification the signal is retransmitted inside the building. This paper presents various approaches for the design, fabrication and testing of microstrip patch antennas and low noise amplifier. A single feed circularly polarized microstrip patch antenna has been designed and fabricated on Quick Circuit CAD/CAM system. The measurements of radiation pattern were done in Compact Antenna Test Range ( CATR ). This antenna has a very low VSWR of 1.39 and a circular gain of 1.92dBi at 1.575GHz. The frequency bandwidth is 35MHz and the polarization of antenna is RHCP. The design of microwave transistor amplifier was carried out using scattering parameters technique. The single stage low noise amplifier was implemented on microstrip circuit by using RT Duroid Roggers Corp. low loss substrate. The measurements of VSWR, Gain and Noise figure were carried out. The single stage LNA has a gain of 11.81dB with a noise figure of 1.84dB. This low noise amplifier and microstrip patch antennas were used for GPS repeater applications. Using this hardware the GPS signal was received inside the building on a GARMIN handheld GPS receiver.