Resonator Introduction
Resonant frequency of the resonator is an electronic component, which is a typical passive devices, peripheral circuits required to drive its work, to generate a clock output. Commonly divided into quartz crystal resonators and ceramic resonators.
Resonator frequency generated from the role, with a stable, well-characterized anti-jamming performance, widely used in various electronic products, quartz crystal resonator frequency accuracy than ceramic resonators, but the cost is high than ceramic resonators. Since the resonator frequency control key role in all the electronic products involved in transmitting and receiving frequency resonator are required. Resonator shape can be divided according to the type of DIP and SMD-two. The most basic resonator is a dielectric resonator device.
Classification and description resonator
Resonator is divided into:
1, quartz crystal resonators: Also known as quartz, commonly known as crystal. Was using the piezoelectric effect of quartz crystal resonator element made with semiconductor devices and RC components used together, can constitute a quartz crystal oscillator.
Piezoelectric effects: Some dielectric applying a mechanical force to cause them to positive and negative charge centers within the relative displacement of the polarization, resulting in the media across the surface of bound charges of opposite sign occur in a range of stress, mechanical strength and charge reversible linear relationship. This phenomenon is called the piezoelectric effect.
Role: to provide system oscillation pulse, stable frequency, select the frequency.
2, ceramic resonators: refers to the resonant frequency of the ceramic shell encapsulation of electronic components. Frequency generated from the role, with a stable, well-characterized anti-jamming performance, widely used in various electronic products, compared with quartz crystal resonators Frequency accuracy is lower, but the cost is lower than the quartz crystal resonator. It is mainly the role of control from the frequency, all the electronic products involved in transmitting and receiving frequency resonator are required.
In the infrared or visible light, ie, when the wavelength of the order of microns applied metal waveguide or cavity more impossible. To this end, the dielectric waveguide and the dielectric resonators developed rapidly and widely applied. Although the dielectric waveguide and the dielectric resonator size can be compared also in the order of a wavelength, but is liable to be made by means of micro-machining small size. For example, cross-sectional size of micron optical fiber and the optical waveguide are all dielectric waveguide. Metal waveguide of the field can be regarded as a plane wave and forth between the conductor surface due to reflection, the dielectric waveguide of the field can be seen as the interface between the medium of electromagnetic waves caused by the total reflection.
Application of the resonator
Metal waveguide cavity with metal widely used in decimeter, centimeter millimeter-wave and long wave band. The cross-section of the waveguide and the resonant cavity size and wavelength are similar, such as a rectangular waveguide operating in the TE01 mode, the wide side is larger than half the wavelength, so that by the millimeter-wave and submillimeter short wave band, metal waveguide and the resonant cavity size is too small, difficult to manufacture. In the infrared or visible light, ie, when the wavelength of the order of microns applied metal waveguide or cavity more impossible. To this end, the dielectric waveguide and the dielectric resonators developed rapidly and widely applied. Although the dielectric waveguide and the dielectric resonator size can be compared also in the order of a wavelength, but is liable to be made by means of micro-machining small size. For example, cross-sectional size of micron optical fiber and the optical waveguide are all dielectric waveguide. Metal waveguide of the field can be regarded as a plane wave and forth between the conductor surface due to reflection, the dielectric waveguide of the field can be seen as the interface between the medium of electromagnetic waves caused by the total reflection. Therefore, the sparse dense medium medium surrounded by a dielectric waveguide is formed. Ideal metal waveguide showed a transverse electromagnetic standing wave in the waveguide beyond the boundaries of near-ideal conductor, there is no electromagnetic field. Dielectric waveguide in the transverse direction was standing wave electromagnetic field, but still exists in the outer dielectric waveguide electromagnetic fields, it was decreasing transverse state, called the evanescent field. The filling of the metal waveguide in a homogeneous medium, TE mode and TM mode can be individually short-circuit of the waveguide wall to meet the boundary condition, so you can always be separated in TE mode and TM mode, they can propagate in the metal waveguide. When two or more metal waveguide filled with a medium, or when part of the filling medium, the electromagnetic field in addition to meeting the conductor wall boundary conditions, must also meet the media interface continuity conditions. Fill in a homogeneous medium in the case of two or more can have a mixed TE and TM modes HEM mode. After understanding the above content later, you can learn more about the next dielectric resonator.
As early as 1939, the dielectric resonator concepts and theories have been proposed, but because it did not find a suitable dielectric material, the theory sleeping for over 20 years, did not get the actual development, to the 1960s high dielectric constant ceramic rutile ceramics (ε ≈ 80100) The successful development of the dielectric resonator has started to be attention. However, because of high temperature coefficient ceramic rutile, limits its practical application. Developed in the 1970s barium titanate and lead zirconate titanate-based ceramic, and their high dielectric, low loss, low temperature coefficient, which makes the dielectric resonator to practical use. Dielectric resonator with small size, light weight, high quality factor, and good stability. In particular, facilitate the application of the microstrip circuits or microwave and millimeter wave integrated circuits, has been paramount, has developed rapidly. When a high dielectric constant of the medium and the air interface is similar open road, the electromagnetic wave at the interface emission coefficient close to 1. Then the dielectric resonator can be regarded as an open circuit surface of the wall, the magnetic wall. So dielectric resonator with homogeneous boundary conditions become a closed system, which is equivalent to an open wall (magnetic wall) cavity.