Dielectric resonators have applications as low-loss compact filters in the microwave region. Tuning characteristics of dielectric resonators that might allow for temperature compensation and frequency variability were investigated both theoretically and experimentally at L band. A secondary dielectric resonator that is offset in frequency from the tuned resonator provides a maximum tuning range of approximately 10 percent before an additional filter loss of 3 dB is incurred; the rate of tuning is slow since it is done by changing the resonator coupling (spacing). For fast tuning, a varactor is used in a coupled resonant circuit. Frequency changes can then be made in a time interval approaching 1/(filter bandwidth), but in this case the maximum tuning range before an additional filter loss of 3 dB is incurred is reduced to 2 percent of the filter frequency.
Die jüngsten Fortschritte im Bereich der drahtlosen Telekommunikation und dem Internet der Dinge sorgen bei drahtlosen Systemen, beim Satellitenfernsehen und bei intelligenten Transportsystemen der 5. Generation für eine höhere Nachfrage nach dielektrischen Materialien und modernen Fertigungstechniken. Diese Materialien bieten ausgezeichnete elektrische, dielektrische und thermische Eigenschaften und verfügen über enormes Potenzial, vor allem bei der drahtlosen Kommunikation, bei flexibler Elektronik und gedruckter Elektronik. Microwave Materials and Applications erläutert die herkömmlichen Methoden zur Messung der dielektrischen Eigenschaften im Mikrowellenbereich, die verschiedenen Ansätze zur Lösung von Problemen der Materialchemie und von Kristallstrukturen, in den Bereichen Doping, Substitution und Aufbau von Verbundwerkstoffen. Besonderer Schwerpunkt liegt auf Verarbeitungstechniken, Einflüssen der Morphologie und der Anwendung von Materialien in der Mikrowellentechnik. Gleichzeitig werden viele der jüngsten Forschungserkenntnisse bei Mikrowellen-Dielektrika und -Anwendungen zusammengefasst. Die verschiedenen Kapitel untersuchen: Oxidkeramiken für dielektrische Resonatoren und Substrate, HTCC-, LTCC- und ULTCC-Bänder für Substrate, Polymer-Keramik-Verbundstoffe für Leiterplatten, Elastomer-Keramik-Verbundstoffe für flexible Elektronik, dielektrische Tinten, Materialien für die EMV-Abschirmung, Mikrowellen-Ferrite. Ein umfassender Anhang präsentiert die grundlegenden Eigenschaften von mehr als 4000 verlustarmen dielektrischen Keramiken, deren Zusammensetzung, kristalline Struktur und dielektrischen Eigenschaften für Mikrowellenanwendungen. Microwave Materials and Applications wirft einen Blick auf sämtliche Aspekte von Mikrowellenmaterialien und -anwendungen, ein nützliches Handbuch für Wissenschaftler, Unternehmen, Ingenieure und Studenten, die sich mit heutigen und neuen Anwendungen in den Bereichen drahtlose Kommunikation und Unterhaltungselektronik beschäftigen.
The resonant frequencies for the fundamental modes in circular cylindrical and rectangular parallelopiped high dielectric resonators have been calculated by computer for a range of values of physical dimensions and relative dielectric constant. The frequency range extends from zero to 50,000 Mc/sec, the relative dielectric constant from 50 to 1800, and physical dimensions from zero to 500 mils. Results are presented in tabular and graphical form with frequency plotted versus resonator length for parametric values of relative dielectric constant and cross sectional dimensions. A brief review of earlier work with high dielectric resonators is included. Expressions for the resonant frequency and fundamental mode field configurations are given. (Author).
The use of dielectric resonator as a resonant antenna was proposed in 1983. Due to the absence of metallic loss, the dielectric resonator antenna (DRA) is highly efficient when operated at millimetre wave frequencies. With the use of high dielectric constant material, the DRA can also be used as a small and low profile antenna operated at low microwave frequencies. Low cost dielectric materials are now easily available commercially, encouraging more antenna engineers to design communication systems with DRAs.
An in-depth look at the state-of-the-art in microwave filter design, implementation, and optimization Thoroughly revised and expanded, this second edition of the popular reference addresses the many important advances that have taken place in the field since the publication of the first edition and includes new chapters on Multiband Filters, Tunable Filters and a chapter devoted to Practical Considerations and Examples. One of the chief constraints in the evolution of wireless communication systems is the scarcity of the available frequency spectrum, thus making frequency spectrum a primary resource to be judiciously shared and optimally utilized. This fundamental limitation, along with atmospheric conditions and interference have long been drivers of intense research and development in the fields of signal processing and filter networks, the two technologies that govern the information capacity of a given frequency spectrum. Written by distinguished experts with a combined century of industrial and academic experience in the field, Microwave Filters for Communication Systems: Provides a coherent, accessible description of system requirements and constraints for microwave filters Covers fundamental considerations in the theory and design of microwave filters and the use of EM techniques to analyze and optimize filter structures Chapters on Multiband Filters and Tunable Filters address the new markets emerging for wireless communication systems and flexible satellite payloads and A chapter devoted to real-world examples and exercises that allow readers to test and fine-tune their grasp of the material covered in various chapters, in effect it provides the roadmap to develop a software laboratory, to analyze, design, and perform system level tradeoffs including EM based tolerance and sensitivity analysis for microwave filters and multiplexers for practical applications. Microwave Filters for Communication Systems provides students and practitioners alike with a solid grounding in the theoretical underpinnings of practical microwave filter and its physical realization using state-of-the-art EM-based techniques.
Novel Technologies for Microwave and Millimeter-Wave Applications provides an overview of current research status in selected field, to facilitate a learning process from concepts to practices, from component design to system architecture, and from small scale to large scale. Each chapter focuses on a topic and is organized to be self-sufficient. Contents in each chapter include concise description of relevant background information, major issues, current trend and future challenges. Useful references are also listed for further reading. Novel Technologies for Microwave and Millimeter-Wave Applications is suitable as a textbook for senior or graduate courses in microwave engineering.
