The Differences Between Dielectric, Coaxial, and Quartz Crystal Resonators


You may be wondering whether dielectric, coaxial, or quartz crystal resonators are the best for your application. To help you decide, here are some of the differences between these resonators:

Dielectric resonators:

The dielectric resonator is a solid puck, either cylindrical, spherical, or parallelepiped shaped. Cylindrical dielectric resonators exhibit a TE01d resonant mode. The electric field is a simple circle concentric with the cylinder's axis. When the dielectric resonator is tuned in this mode, the magnetic energy in the material is stored for more than 60% of its lifetime. Afterwards, the magnetic energy decays rapidly as the material is moved farther away from the resonator surface.


A ceramic dielectric resonator can have many benefits over metal cavity resonators. Dielectric resonators have a much higher unloaded Q factor, are lighter and are widely available. In addition, they are easy to manufacture, and their Q factor can range from the low 10s to the high 1000s. The following sections provide an overview of the characteristics of ceramic dielectric resonators.

High-permeability materials like CaTiO3 can create strong, uniform magnetic fields. This can solve the problems associated with RF coils that operate in high fields. Ceramic dielectric resonators, based on high permittivity materials, can create such strong fields in a compact structure. A typical ceramic dielectric resonator made of CaTiO 3 has a relative permittivity value of 156 and a Q value of over 2000. Because the electric field is confined within the dielectric material, losses are minimized, and the Q factor is higher, the CaTiO 3 dielectric resonator is ideal for various applications.

Super-high-Q resonators are very difficult to produce and require considerable expertise in manufacturing and research in dielectric materials. To create these resonators, developing a series of complex test cavities is necessary. Ultimately, it would help if you chose a high-quality ceramic resonator that can withstand a wide range of frequencies. The resonator should meet your expectations for performance.

Coaxial ceramic resonators:

Ceramic resonators are piezoelectric resonators that function on the mechanical resonance of the materials used. To produce this frequency, the ceramic material is patterned with two metal electrodes on opposite sides of the substrate. When a voltage is applied to the electrodes, the resulting mechanical vibrations generate an oscillating voltage. This material is also known as SAW, or Surface Acoustic Wave resonators. They are common in the construction of oscillators like crystal resonators.

The structure of coaxial ceramic resonators depends on boundary conditions, and there are three basic types: half-wavelength, quarter-wavelength, and capacitive load. The Direct (DR) series has two ports and is a compact and temperature-stable resonator. This device is ideal in various microwave communications equipment, including PCS/PCN filters, base stations, satellite broadcast reception systems, and military microwave facilities.


The main advantages of ceramic coaxial resonators are their compact size and high-quality performance. They are better than Butterworth and Chebyshev filters for a variety of applications. They are also lightweight and easy to manufacture. The measurement data of the ceramic resonators is suitable for developing an accurate model of the ceramic coaxial resonator. The resonator is then placed in a metallic casing.

IMC resonators' advantages include increasing the capacitor value by soldering the series capacitance element to the resonator's ID. The downsides include low Q and microphonic noise. This problem is overcome with a patented oscillator topology. The topology incorporates feedback resistance to decrease thermal drift. The patent-pending approach also includes a methodology for coupling resonators.

Quartz crystal resonators:

Unlike LC circuits, ceramic and quartz crystal resonators are passive components, requiring no tuning. However, manufacturers must choose certain parameters specific to the crystal's operation. The decision may depend on other electronic components in the circuit or on the overall design of the electronics. This article will discuss the differences between these two types of resonators. We'll also discuss some common uses of quartz crystals and their advantages.

First, let's discuss what a resonator is. A resonator's mechanical Q (Qm) refers to its resonant ability. Hence, a resonator is suitable as a replacement for an inductor in a Colpitts circuit. Secondly, resonators are designed to operate at various frequencies and vibration modes.

The other common application for a quartz crystal resonator is in filters. Their high-quality properties make them ideal for rejecting unwanted signals. Quartz crystal filters may consist of just one or several crystals, while more complicated ones may have six or eight. Advanced RF circuit design usually involves the development of filters that employ these resonators. This process is similar to that of semiconductor manufacturing. In addition, it is a cost-effective option and offers high-quality resonators.

Although ceramic and quartz crystal resonators are similar in appearance and function, they have some distinct differences. Quartz crystal resonators are more accurate and have a tighter frequency tolerance than ceramic resonators. Ceramic resonators are smaller and less expensive than crystals but lack temperature and frequency stability. Besides, ceramic resonators have a low accuracy of about 1% to 0.1 percent.