Our range of RF capacitors offers capacitance values from 0.1pF to 0.1µF, and voltage ratings from 2V to 2.5kV.
What is an RF Capacitor?
An RF capacitor is a capacitor with material and design characteristics optimised for RF frequencies. The key characteristics are:
- Lowest possible Equivalent Series Resistance (ESR) at RF frequencies
- High Q at RF frequencies
- Minimal capacitance change with temperature
- High series resonant frequency (SRF)
What is an RF Capacitor used for?
RF capacitors are used for various functions such as DC blocking, bypass, filtering, and impedance matching. Common applications include the following:
- RF power amplifiers (PA)
- Cellular base stations (4G, 5G)
- Wireless LAN
- Telecommunication Networks
- GPS
- Keyless entry systems
- Bluetooth
- Automotive V2X, Safety Systems, Power Train, Communication Systems
What capacitors are best for RF?
Single layer capacitors (SLCs) are specifically designed for use in microwave and RF applications. This is because the inherent self-resonant frequency (SRF), which is the point where the capacitor will exhibit the least amount of impedance, of an SLC is the highest of any discrete lumped constant capacitor. Capacitors with a high SRF have low equivalent series resistance (ESR), which is the internal resistance in the capacitor that appears in series with the capacitance of the device. This is important because, in general, ESR increases as frequency increases, so using a capacitor that has inherently low ESR is necessary. Additionally, since SLCs are formed monolithically, the number of mechanical parts in the SLC is limited, which also contributes to a lower ESR value. One potential drawback of SLCs is that since they comprise just a single layer of material, capacitance is heavily dependent on the dielectric constant of the dielectric used, which limits the capacitance that can be achieved. Therefore, SLCs are mainly ideal for high-frequency, low-capacitance applications.
