We look for materials with good SAW resonator properties and with the largest difference between temperature responses of resonators in a pair on a single substrate. We have identified several cuts of quartz having useful properties with TCF difference up to 140 ppm/°C for a pair of resonators on a single substrate. As a rule, placing of such resonators on a single substrate requires rotation by up to 90° relative to each other thus increasing the die size. The limited range of cuts presents a unique opportunity to place both resonators along the X+90° direction with one resonator using BGS waves (with electrodes placed along X axis) and the other one (with electrodes inclined by about ±10° to X axis) using Rayleigh waves. These cuts are close to the 70°Y-cut where high TCF difference is reached together with acceptable characteristics of resonators. Resonators were designed for all useful cuts (including the 70°Ycut) and tested. The use of different periods in reflectors and IDT together with individual choice of gaps between reflectors and IDT allowed obtaining low spurious content in resonatorresponses. The quality factors reached values up to 4000 at central frequencies around 915 MHz for both BGS and Rayleigh types of waves. The measured difference of TCF is about 138 ppm/°C on 70°Y-cut that is close to the calculated value.
The unidirectional interdigital transducer topology features when designing SAW filters are considered. As well there are considered physical properties of various piezo‑crystals with different types of cut that allow to realize unidirectional operation of interdigital transducer. There are analyzed the conditions when the »natural» directivity of interdigital transducer becomes possible, topological variety of such transducers are considered. Various types of topology for transducers with a constant aperture are presented. Influence of the form, topology and dimensions of electrodes on characteristics of devices with directional interdigital transducers is analyzed. Influence of substrates technological parameters and interdigital transducers elements (electrodes material and thickness, substrate crystals types and cuts) on the value of attenuation and level of false signals is considered. Articles of functional electronics and SAW piezoelectric filters are used in various radio systems. Creation of passive wireless monitoring systems with use of SAW devices is considered as a separate direction of research.
It is proposed the appearance and the main architectural concepts of distributed hardware and information‑calculating medium construction for sixth generation aviation complexes. An essence of characteristics and principles of sixth generation on‑board avionics complexes construction is revealed. There are shown the main principles of sixth generation on‑board avionics complexes, such as: centralized architecture of integrated information and control medium; high‑intelligence cockpit designed based of interactive technique and expert systems; unified core part of on‑board avionics complexes’ units; jam‑resistant communication system with use of Internet technologies. There are defined the main principles of sixth generation on‑board avionics complexes designing: integration of on‑board avionics complexes’ elements and flight vehicles, centralized architecture of information‑and‑control computing system, wide use of self-earning expert systems, communication system with use of Internet technologies, decision‑making self-earning expert systems, construction of high‑intelligence cockpit on the basis of interactive technique, maximal unification of on‑board avionics complexes’ elements.
The results of modeling the processes of receiving and processing the signals of remote sensing of the Earth’s surface using helicopter radar and synthesizing the antenna aperture due to its placement on the rotating rotor blades are presented. The mathematical correctness of the application of the developed algorithms for processing probing signals, as well as the uniqueness of the measurements, was confirmed. At the same time, the dimensions of the synthesized aperture due to the rotation of the radiator placed at the end of the propeller blade are equivalent to a circular antenna array with a diameter of tens of meters. The functionality of the remote sensing system based on this radar meets the requirements for ice observation and navigation systems for seagoing ships off the coast. The simulation results confirm the promise of further research in this direction and can be used in the development of radar systems with synthesized antenna aperture mounted on rotating rotor blades.
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