Resonator types, basics and difference between - coaxial, dielectric, crystal, ceramic, SAW, YIG resonator
This page covers types and basics of resonators and difference between them. It includes ceramic coaxial resonator, dielectric resonator, crystal resonator, ceramic resonator, SAW resonator and YIG resonator. The page also covers vendors/manufacturers of these type of resonators.
Ceramic Coaxial Resonator
Figure 1: Coaxial resonator
It is basically coaxial line constructed using ceramic. They are implemented as high Q inductor which when combined with capacitor will create resonant circuit. Figure-1 depicts coaxial resonator which is a square shaped outer conductor and cylindrical shaped inner conductor.
There are two forms of coaxial resonator as shown in the figure-1.
• λ/4 resonator with one end shorted and the other open
• λ/2 resonator with both ends open
Applications: VCOs, Filters, Coaxial resonator oscillators.
Vendors: Integrated Microwave Corp., Trans-Tech, Tusonix, Temex Ceramics
Figure 2: Dielectric resonator
It is a disc shaped structure with high εr. EM fields are limited within dielectric resonator which allows radiation losses to be very small. This results into high Q resonator.
There are many modes in which dielectric resonator works. The most common mode is TE01 i.e. transverse electric.
Frequency range: 260 MHz to about 50 GHz.
Applications: Oscillators, microwave filters, microwave combiners, satellite equipments
Vendors: MCV Microwave, Temex Ceramics, Trans-Tech
Figure 3: Crystal resonator
The quartz crystal resonator is constructed by placing slice of quartz between two electrodes. Slice is achieved by variety of cuts such as AT-Cut and SC-Cut.
Quartz crystal's piezoelectric properties are used as frequency control elements in this type of
resonator. Piezoelectric materials are used to convert mechanical energy into electrical and vice versa.
READ MORE Quartz Crystal >>
Frequency range: 1.8432 to about 250 MHz
Applications: Satellites, Mobile devices, TVs, home appliances, automotive
Vendors: IQD, Vectron, Oscilent, Murata, Abracon
Figure 4: Ceramic resonator
The main benefit of ceramic resonator is less start-up time in comparison to quartz crystal resonator. It works based on principle of mechanical resonance of piezoelectric ceramics. It is constructed using two metal electrodes on both the sides of ceramic substrate.
The figure depicts equivalent circuit of ceramic resonator. Substrate between the electrodes vibrate when voltage is applied. The resonant frequency here depends on thickness of the substrate.
Applications: Automotive, medical, communications, healthcare Vendors: Murata, Abracon, Oscilent
Figure 5: SAW resonator
SAW stands for Surface Acoustic Wave. These waves propagate at the surface of crystal of piezoelectric type in order to carry information. The SAW resonators are used to construct oscillators like crystal resonators.
Frequency range: Available upto 1.1 GHz
Vendors: ECS Inc. International, Murata, Abracon, Golledge Electronics
Applications: High Frequency Oscillators, Band Pass Filters(BPFs), security devices, door openers, keyless devices etc.
READ MORE SAW Filter Basics and Vendors >>
Figure 6: YIG Topologies
The YIG is basically crystal devices which have high Q and hence are used to develop oscillators of very low phase noise.
It will resonate when immersed in the DC magnetic field region.
The resonance is directly proportional to magnitude of applied magnetic field.
This can be generated using magnets of various types.
Frequency Range: Upto about 50 GHz.
Applications: Filters and Oscillators
Vendors: Micro Lambda Wireless,
READ MORE YIG Oscillator >>