Microwave devices based on tunable materials are one of the focuses of current dielectric application research. Typical applications include phase shifter

antenna beam control

resonator

filter

voltage controlled oscillator

matching network and tunable power distributor

etc. Tunable capacitor is the core of tunable microwave devices. Based on the comparison of the structural properties of capacitors

this review systematically discusses the relationship between the structure and dielectric tunable properties of various materials including biopolymers

metal-organic frameworks

ceramicpolymer composites

liquid crystals and fluoropolymers. The results show that fluoropolymers can be promising candidate materials for many new applications due to their mechanical flexibility

ease of processing and light weight. This article can also offer help for various microwave applications in material selection and other aspects.