Bias Tees

We are happy to introduce our new Bias Tees by HASCO. HASCO Bias Tees are an ultra-boadband design, operating from 200 MHz to 40 GHz. They are capable of biasing up to 50 VDC (Volts DC) and 225 mA (milliamps) with a VSWR of 2:1 across the full band.

A bias tee is a diplexer, which splits incoming signals from a common port into two paths (sometimes called "channels"), dependent on frequency. It is a three-port network used to supply DC currents or voltages to RF devices, and for setting the DC bias point, without disturbing other components. The DC port injects a bias onto the RF path by adding a DC bias level to a radio-frequency signal from the RF port onto the RF-DC port. The biased RF signal can be sent to a remote device to provide both an RF signal and a DC supply.

In the figure below, an RF signal is introduced to the RF & DC port and a DC bias is added from the DC Only port. A Bias Tee can also work in reverse order to remove a DC bias that is received from the RF & DC port, while allowing only the RF signal to pass to the RF port. In the reverse scenario, the DC Only port can be connected to a VDC port of an active device, such as an amplifier, to power it.

Properties that are important to a bias tee are RF bandwidth, insertion loss and mismatch at the two RF ports, the maximum DC current, and video bandwidth of the DC port.