DC-blocks and Bias-Tees
The DC blocks and Bias-Ts block or inject a DC voltage onto a coaxial RF link. DC blocks are used to protect equipment and/or to improve the accuracy of measurements. Bias-Ts have many applications that all revolve around providing a DC voltage onto an RF link in order to carry DC power and an RF signal over the same link. For example, they are used to power laser diodes in telecommunications systems, to measure the S-parameters of active discrete components, and to supply power to external LNAs.
The DC blocks and Bias-Ts in this category are all broadband devices.
Subcategories
-
DC-Blocks
A DC-block blocks DC content from an AC signal. It is used to to protect sensitive equipment or to minimize DC signals that would otherwise influence the performance of the system or stage the signal is fed to.
- Bandwidth : 20kHz - 5 GHz
- Insertion loss < 0.5 dB
- Very high return loss of 20 dB or better
- Solid aluminium case
A DC block is used to protect sensitive equipment from any DC component or to improve measurement accuracy by removing any DC offset that may otherwise influence a measurement device negatively.
-
Bias-Tees
These devices are used to provide DC power over an RF coaxial cable to power RF devices (for example, an LNA close to an antenna). In a typical application, two bias tees are used, one to inject power and another to extract power. DC power can be applied or retracted by means of an SMA connector or a set of turret/feedthrough capacitor terminals.
Other applications include biasing a laser diode in telecommunications systems or biasing a semiconductor (such as a BJT) to measure its performance (s-parameter measurements).
The bias-Ts in this category are designed for demanding wide-band applications that must operate at near-ideal levels. The bias-T circuits are tuned for a very flat frequency response, have high RF-to-DC isolation, and excellent return loss at the RF ports.============================================================
