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This paper describes several small printed circuit board planar antennas that can be integrated with amplifiers for short-range vehicle wireless communication. The antennas are designed for the 315-MHz frequency band, which is commonly used for control and security devices in the USA and Canada. Each antenna has dimensions of 50 × 70 mm (much less than the free-space wavelength λ = 0.95 m) and is implemented on FR-4 dielectric substrate. These investigated antennas were compared with respect to input impedance, radiation resistance, radiation efficiency, directivity, directionality, bandwidth, matching system complexity, and gain. This paper also includes experimental verification of the final antenna design in the vehicle. It is shown that the antenna diversity method can increase communication range for remote keyless entry systems. [ABSTRACT FROM AUTHOR]

With the widespread popularity and reliability of microcomputers and the availability of easy-to-use application generators and application packages, it has become possible to introduce computer systems into environments where this was not practical either from a technical or an economic standpoint. This paper will describe how an integrated, multi-application system was developed and successfully implemented two years ago for a forest products company. Emphasis will be placed on: * How the application generator aided or constrained development. * How the development process and system design differed from the traditional approach, in view of the requirement that the system should operate entirely without trained technical support. [ABSTRACT FROM AUTHOR]