Coaxial Bias Tee
Coaxial Bias Tee allows simultaneous injection of DC bias and RF signals into microwave circuits while maintaining signal integrity. Ideal for powering RF amplifiers, active antennas, microwave modules, RF test systems, satellite communication equipment and millimeter-wave measurement setups.
Precision Coaxial Bias Tees for Broadband DC and RF Routing
AO Microwave’s high-performance coaxial bias tees are designed to inject DC current into active RF transmission lines with minimum signal loss. Built with rugged, passivated aluminum and copper housings, these diplexers incorporate a series DC-blocking capacitor and a shunt RF-blocking inductor. Operating up to 50 GHz with standard connector interfaces (SMA, N-type, and 2.92mm), our bias tees achieve low insertion losses (typically < 0.50 dB), excellent input VSWR of < 1.25:1, and an outstanding RF-to-DC isolation of typically > 35 dB across the band.
By establishing a highly isolated path between the DC and RF terminals, our bias tees prevent high-frequency leakage from corrupting external DC power supplies. They are critical for biasing active MMICs (LNAs, HPAs), feeding active antennas, and testing active devices in laboratory environments.
| Part No | Frequency/GHz | Return Loss (Typ) | IL/dB (Typ) | Isolation/dB (Typ) | Power/W (Max) | Voltage/V | Current/mA | RF Connector Type | DC Connector Type |
|---|---|---|---|---|---|---|---|---|---|
| AO30K18G-CBT2-SKSK30 | 30KHz-18GHz | 12 | 2 | 30 | 2 | +50 | 500 | SMA Female | SMA Female |
| AO30K26.5G-CBT2-SKSK30 | 30KHz-26.5GHz | 12 | 2 | 30 | 2 | +50 | 700 | SMA Female | SMA Female |
| AO10M26.5G-CBT5-3.5KSK30 | 10MHz-26.5GHz | 12 | 2.5 | 30 | 5 | +50 | 500 | 3.5mm Female | SMA Female |
| AO30K40G-CBT2-2.92KSK30 | 30KHz-40GHz | 12 | 2.5 | 30 | 2 | +50 | 500 | 2.92mm Female | SMA Female |
| AO30K50G-CBT5-2.4KSK30 | 30KHz-50GHz | 12 | 3 | 30 | 5 | +25 | 500 | 2.4mm Female | SMA Female |
| AO10M50G-CBT5-2.4KSK30 | 10MHz-50GHz | 12 | 3 | 30 | 5 | +50 | 500 | 2.4mm Female | SMA Female |
| AO30K67G-CBT1-1.85KSK25 | 30KHz-67GHz | 10 | 4 | 25 | 1 | +25 | 500 | 1.85mm Female | SMA Female |
| AO30K70G-CBT1-1.85KSK25 | 30KHz-70GHz | 10 | 4 | 25 | 1 | +25 | 500 | 1.85mm Female | SMA Female |
| AO200K110G-CBT1-1.0KSK25 | 200KHz-110GHz | 12 | 4 | 25 | 1 | +10 | 170 | 1.0mm Female | SMA Female |
The Electromagnetics of Broad-Band Inductor Self-Resonance
Bias tees act as diplexers, splitting high-frequency RF signals and low-frequency DC bias currents. In a standard bias tee, a series capacitor blocks DC from entering the RF port, while a shunt inductor blocks RF from entering the DC port.
At high microwave frequencies, the shunt inductor exhibits parasitic capacitance, creating a self-resonant frequency (SRF). Above this self-resonant point, the inductor behaves capacitively, allowing RF energy to leak into the DC port. This leakage degrades overall system performance. AO Microwave resolves this high-frequency leakage by using conical or multi-stage inductors. This design distributes parasitic resonances, maintaining high RF-to-DC isolation (typically > 35 dB) and low insertion loss across the entire operating band.
Target Applications & Operational Advantages
By establishing highly isolated DC and RF routing paths, our coaxial bias tees secure active component biasing:
Active MMIC Biasing (LNAs & HPAs)
Function: Injects DC bias voltage into active amplifiers while preserving the high-frequency RF signal path.
Advantage: High RF-to-DC isolation prevents RF energy from feeding back into and damaging external DC power supplies.
Active Antenna Power Feeding
Function: Feeds DC power to remote, mast-mounted active antennas through the same coaxial signal cable.
Advantage: Low insertion loss (<0.5 dB) preserves system noise figure, maintaining receiver sensitivity.
Active Device Laboratory Testing
Function: Biases transistors under test inside automated measurement setups.
Advantage: Low VSWR and flat frequency response ensure accurate S-parameter measurements across full frequency sweeps.
Coaxial Bias Tee FAQs
Need high-isolation Coaxial Bias Tees?
Specify your connector interface (SMA/2.92mm), frequency range, maximum DC current, and voltage limit — we'll quote in 24 hours.
