Dual-band Input Coupling Structure Integrated Acoustic Path - Programmable Sound Saw Filter Structure

A sonic device, which integrats two interdigital transducers of different frequencies amd ten same interdigital transducers with multiple couplers, is developed. This is based on the theory and technology of surface acoustic wave (SAW) filter. The frequencies of two input interdigital transducers are individually 180MHz and 140MHz with the same bandwidth of 20MHz. The surface acoustic wave generated by the input is coupled to the output which is composed with ten same structure IDTs. The ten output signals generated by output IDTs can be weighted and summed. The frequency response of this device can be changed in the range from 100MHz to 200MHz with 4M1-lz--12MHz bandwidth. The insertion loss is about -30dB--- -45dB. A multi-chip mode (MCM) programmable SAW filter can be realized if this device is combined with I ii m CMOS programmable developed ASIC. There are five chapters in this thesis, and mean points are as follow: Chapter One: The SAW technology and its application are introduced. Two basic structures used in this research are interdigital transducer and multi-stripe coupler. Then the principle and application of them are discussed. Chapter Two: The principle, background and application of the SAW filter and the programmable SAW filter are discussed. Chapter Three: The structure and the principle of the sonic device is shown and discussed. Then the characteristic of the device is listed and simulated. At last the fabrication process is presented. Chapter Four: The testing principle of the acoustic device is discussed firstly. Then testing results of the device are shown and discussed with the help of MATLAB. Last: The conclusion is drawn, and some advice is given. This program is a new conception of solid-state integrated microwave electronic devices combining microelectronic technology with surface acoustic wave technology. So this research can be used as the basic technology of the next generation of filters at the antenna in the communication and network. A programmable bandwidth SAW filter at the antenna can provide the required selectivity of received wireless signal for the radio with high sensitivity and low noise. It is also a key kind of electron device in the software signal processing system and software programmable integrated electronic system. In this way, the conventional tuning-receiving technology is completely changed. This research has various and important applications in many fields such as cellular phone system, computer network communication, military electronic countermeasure technology and GPS etc.