90° & 180° Hybrid Couplers
3 dB Hybrid Couplers for Quadrature Splitting, Balanced Amplifier Design, and Antenna Feed Networks
Hybrid couplers are four-port directional couplers built for a 3 dB equal power split. What separates them from standard power dividers is the controlled phase relationship between output ports. A 90 degree hybrid, also called a quadrature hybrid or branch line coupler, delivers two equal-amplitude output signals with exactly 90 degrees of phase difference between them.
A 180 degree hybrid, also called a rat race coupler, delivers two equal-amplitude outputs that are either in phase or 180 degrees out of phase depending on which input port is driven. That phase control is what makes hybrids the building block of choice for balanced amplifiers, image rejection mixers, reflection phase shifters, and antenna beam forming networks.
Octave Band, Special Band, Multi Band and Ultra Wide-Band Models Available
Excellent Amplitude and Phase Tracking with Solid Build Construction
Many In-Stock Models and Custom Designs Available
MCLI has developed a line of 3 dB hybrid couplers featuring broad bandwidths alongside tight amplitude and phase balance specifications. The product line spans stripline and lumped element construction, covering frequencies from DC to 60 GHz at power levels from 1 watt to 2,000 watts, with series available for both 90 degree and 180 degree applications across commercial and defense markets.
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Showing 1–100 of 276 results
| Part # | Frequency Range (GHz) | Insertion Loss (dB) | Isolation (dB) | VSWR In/Out | Amplitude Balance | Phase Balance | Power Avg. (W) | Lead Time | Notes | Action | |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Min | Max | ||||||||||
| JL-17 | 0.00001 | 0.06 | 0.7 | 20 | 1.30:1 | 0.2 | 2 | 1 | 4-6 Weeks | N/A | Request Quote |
| JL-17/NF | 0.00001 | 0.06 | 0.7 | 20 | 1.30:1 | 0.2 | 2 | 3 | 4-6 Weeks | N/A | Request Quote |
| HCD-1 | 0.0001 | 0.05 | 0.5 | 30 | 1.30:1 | 0.2 | 6 | 500 | 9-10 Weeks | N/A | Request Quote |
| HCD-2 | 0.0001 | 0.25 | 1 | 18 | 1.40:1 | 0.6 | 8 | 100 | 9-10 Weeks | N/A | Request Quote |
| HJ-1/HP | 0.0001 | 0.05 | 0.5 | 30 | 1.30:1 | 0.5 | 6 | 500 | 4-6 Weeks | N/A | Request Quote |
| HCD-4 | 0.0002 | 0.035 | 0.4 | 20 | 1.30:1 | 0.2 | 5 | 50 | 9-10 Weeks | N/A | Request Quote |
| HCD-5 | 0.0003 | 0.1 | 1 | 20 | 1.50:1 | 0.3 | 5 | 100 | 9-10 Weeks | N/A | Request Quote |
| HCD-6 | 0.002 | 0.032 | 0.2 | 25 | 1.30:1 | 0.1 | 3 | 500 | 9-10 Weeks | N/A | Request Quote |
| HCD-7 | 0.002 | 0.032 | 0.3 | 20 | 1.30:1 | 0.1 | 5 | 1,000 | 9-10 Weeks | N/A | Request Quote |
| JL-15 | 0.002 | 0.2 | 1.2 | 20 | N/A | 0.3 | 3 | 1 | 4-6 Weeks | N/A | Request Quote |
| JL-16 | 0.002 | 0.2 | 0.75 | 30 | 1.30:1 | 0.2 | 2 | 1 | 4-6 Weeks | N/A | Request Quote |
| JL-25 | 0.002 | 0.4 | 2.5 | 15 | 1.50:1 | 0.3 | 5 | 1 | 4-6 Weeks | N/A | Request Quote |
| JL-16/NF | 0.002 | 0.2 | 0.75 | 20 | 1.30:1 | 0.2 | 2 | 1 | 4-6 Weeks | N/A | Request Quote |
| JL-25/NF | 0.002 | 0.4 | 2.5 | 15 | 1.50:1 | 0.3 | 5 | 1 | 4-6 Weeks | N/A | Request Quote |
| JL-11 | 0.003 | 0.03 | 0.8 | 20 | 1.30:1 | 0.2 | 2 | 1 | 4-6 Weeks | N/A | Request Quote |
| JL-11/NF | 0.003 | 0.03 | 0.8 | 20 | 1.30:1 | 0.2 | 2 | 1 | 4-6 Weeks | N/A | Request Quote |
| JL-14 | 0.005 | 0.4 | 1.5 | 20 | 1.50:1 | 0.4 | 6 | 1 | 4-6 Weeks | N/A | Request Quote |
| JL-24 | 0.005 | 0.2 | 1.4 | 25 | 1.50:1 | 0.4 | 4 | 1 | 4-6 Weeks | N/A | Request Quote |
| JL-14/NF | 0.005 | 0.4 | 1.5 | 20 | 1.50:1 | 0.4 | 6 | 1 | 4-6 Weeks | N/A | Request Quote |
| JL-24/NF | 0.005 | 0.2 | 1.4 | 25 | 1.50:1 | 0.4 | 4 | 1 | 4-6 Weeks | N/A | Request Quote |
| JL-1 | 0.01 | 0.02 | 0.8 | 20 | 1.30:1 | 0.2 | 2 | 1 | Stock - 1 Week | N/A | Request Quote |
| JL-1/NF | 0.01 | 0.02 | 0.8 | 20 | 1.30:1 | 0.2 | 2 | 1 | 4-6 Weeks | N/A | Request Quote |
| HL-1 | 0.0107 | 0.0107 | 0.5 | 25 | 1.20:1 | 0.2 | 2 | 1 | 4-6 Weeks | N/A | Request Quote |
| HL-1/NF | 0.0107 | 0.0107 | 0.5 | 25 | 1.20:1 | 0.2 | 2 | 1 | 4-6 Weeks | N/A | Request Quote |
| HL-2 | 0.02 | 0.02 | 0.5 | 25 | 1.20:1 | 0.2 | 2 | 1 | 4-6 Weeks | N/A | Request Quote |
| HL-2/NF | 0.02 | 0.02 | 0.5 | 25 | 1.20:1 | 0.2 | 2 | 1 | 4-6 Weeks | N/A | Request Quote |
| HB-56-200 | 0.02 | 0.5 | 0.6 | 20 | 1.40:1 | 0.3 | 5 | 200 | 9-10 Weeks | N/A | Request Quote |
| HB-56-200/SMAF | 0.02 | 0.5 | 0.6 | 20 | 1.40:1 | 0.3 | 5 | 200 | 9-10 Weeks | N/A | Request Quote |
| HB-56-200/NF | 0.02 | 0.5 | 0.6 | 20 | 1.40:1 | 0.3 | 5 | 200 | 9-10 Weeks | N/A | Request Quote |
| HB-96 | 0.02 | 0.52 | 0.6 | 20 | 1.30:1 | 0.3 | 5 | 250 | 9-10 Weeks | N/A | Request Quote |
| HCD-8 | 0.02 | 0.15 | 0.5 | 20 | 1.30:1 | 0.3 | 5 | 100 | 9-10 Weeks | N/A | Request Quote |
| HCD-9 | 0.02 | 0.15 | 0.5 | 20 | 1.30:1 | 0.2 | 5 | 200 | 9-10 Weeks | N/A | Request Quote |
| HCD-10 | 0.02 | 0.512 | 0.8 | 25 | 1.40:1 | 0.4 | 5 | 20 | 9-10 Weeks | N/A | Request Quote |
| HCD-11 | 0.02 | 0.512 | 0.8 | 25 | 1.40:1 | 0.4 | 5 | 50 | 9-10 Weeks | N/A | Request Quote |
| HCD-12 | 0.02 | 0.512 | 0.6 | 20 | 1.40:1 | 0.4 | 5 | 100 | 9-10 Weeks | N/A | Request Quote |
| HCD-13 | 0.02 | 1 | 1.3 | 20 | 1.40:1 | 0.4 | 5 | 20 | 9-10 Weeks | N/A | Request Quote |
| JL-2 | 0.02 | 0.04 | 0.8 | 20 | 1.30:1 | 0.2 | 2 | 1 | 4-6 Weeks | N/A | Request Quote |
| JL-13 | 0.02 | 1 | 1.5 | 17 | 2.00:1 | 0.5 | 7 | 1 | 4-6 Weeks | N/A | Request Quote |
| JL-22 | 0.02 | 1 | 2.3 | 15 | 1.30:1 | 1 | 5 | 1 | 4-6 Weeks | N/A | Request Quote |
| JL-26 | 0.02 | 1.2 | 1.6 | 26 | 1.30:1 | 0.4 | 4 | 1 | 4-6 Weeks | N/A | Request Quote |
| JL-2/NF | 0.02 | 0.04 | 0.8 | 20 | 1.30:1 | 0.2 | 2 | 1 | 4-6 Weeks | N/A | Request Quote |
| JL-13/NF | 0.02 | 1 | 1.5 | 17 | 2.00:1 | 0.5 | 7 | 1 | 4-6 Weeks | N/A | Request Quote |
| JL-22/NF | 0.02 | 1 | 2.3 | 15 | 1.30:1 | 1 | 5 | 1 | 4-6 Weeks | N/A | Request Quote |
| JL-26/NF | 0.02 | 1.2 | 1.6 | 26 | 1.30:1 | 0.4 | 4 | 1 | 4-6 Weeks | N/A | Request Quote |
| HL-3 | 0.0214 | 0.0214 | 0.5 | 25 | 1.20:1 | 0.2 | 2 | 1 | 4-6 Weeks | N/A | Request Quote |
| HL-3/NF | 0.0214 | 0.0214 | 0.5 | 25 | 1.20:1 | 0.2 | 2 | 1 | 4-6 Weeks | N/A | Request Quote |
| HL-4 | 0.03 | 0.03 | 0.5 | 25 | 1.20:1 | 0.2 | 2 | 1 | 4-6 Weeks | N/A | Request Quote |
| HL-4/NF | 0.03 | 0.03 | 0.5 | 25 | 1.20:1 | 0.2 | 2 | 1 | 4-6 Weeks | N/A | Request Quote |
| JL-27S | 0.03 | 0.45 | 1.2 | 18 | 1.25:1 | 0.8 | 4 | 5 | 4-6 Weeks | N/A | Request Quote |
| HL-5 | 0.04 | 0.04 | 0.5 | 25 | 1.20:1 | 0.2 | 2 | 1 | 4-6 Weeks | N/A | Request Quote |
| HL-5/NF | 0.04 | 0.04 | 0.5 | 25 | 1.20:1 | 0.2 | 2 | 1 | 4-6 Weeks | N/A | Request Quote |
| JL-3 | 0.04 | 0.08 | 1 | 20 | 1.30:1 | 0.6 | 2 | 1 | 4-6 Weeks | N/A | Request Quote |
| JL-3/NF | 0.04 | 0.08 | 1 | 20 | 1.30:1 | 0.6 | 2 | 1 | 4-6 Weeks | N/A | Request Quote |
| JL-4 | 0.05 | 0.1 | 1 | 20 | 1.30:1 | 0.6 | 3 | 1 | 4-6 Weeks | N/A | Request Quote |
| JL-12 | 0.05 | 1 | 2.8 | 12 | 1.50:1 | 1 | 10 | 1 | 4-6 Weeks | N/A | Request Quote |
| JL-4/NF | 0.05 | 0.1 | 1 | 20 | 1.30:1 | 0.6 | 3 | 1 | 4-6 Weeks | N/A | Request Quote |
| JL-12/NF | 0.05 | 1 | 2.8 | 12 | 1.50:1 | 1 | 10 | 1 | 4-6 Weeks | N/A | Request Quote |
| HL-6 | 0.06 | 0.06 | 0.5 | 25 | 1.20:1 | 0.2 | 2 | 1 | 4-6 Weeks | N/A | Request Quote |
| HL-6/NF | 0.06 | 0.06 | 0.5 | 25 | 1.20:1 | 0.2 | 2 | 1 | 4-6 Weeks | N/A | Request Quote |
| JL-5 | 0.06 | 0.12 | 1 | 20 | 1.30:1 | 0.6 | 3 | 1 | 4-6 Weeks | N/A | Request Quote |
| JL-5/NF | 0.06 | 0.12 | 1 | 20 | 1.30:1 | 0.6 | 3 | 1 | 4-6 Weeks | N/A | Request Quote |
| HL-7 | 0.063 | 0.063 | 0.5 | 25 | 1.20:1 | 0.3 | 2 | 1 | 4-6 Weeks | N/A | Request Quote |
| HL-7/NF | 0.063 | 0.063 | 0.5 | 25 | 1.20:1 | 0.3 | 2 | 1 | 4-6 Weeks | N/A | Request Quote |
| HL-8 | 0.07 | 0.07 | 0.5 | 20 | 1.20:1 | 0.3 | 2 | 1 | 4-6 Weeks | N/A | Request Quote |
| HL-8/NF | 0.07 | 0.07 | 0.5 | 20 | 1.20:1 | 0.3 | 2 | 1 | 4-6 Weeks | N/A | Request Quote |
| HL-9 | 0.08 | 0.08 | 0.5 | 20 | 1.20:1 | 0.3 | 2.5 | 1 | 4-6 Weeks | N/A | Request Quote |
| HL-9/NF | 0.08 | 0.08 | 0.5 | 20 | 1.20:1 | 0.3 | 2.5 | 1 | 4-6 Weeks | N/A | Request Quote |
| HB-97 | 0.08 | 1 | 1 | 16 | 1.40:1 | 1 | 5 | 100 | 9-10 Weeks | N/A | Request Quote |
| JL-6 | 0.08 | 0.16 | 1.2 | 20 | 1.30:1 | 0.6 | 3 | 1 | 4-6 Weeks | N/A | Request Quote |
| JL-6/NF | 0.08 | 0.16 | 1.2 | 20 | 1.30:1 | 0.6 | 3 | 1 | 4-6 Weeks | N/A | Request Quote |
| HCD-17 | 0.088 | 0.108 | 0.2 | 20 | 1.30:1 | 0.1 | 3 | 1,200 | 9-10 Weeks | N/A | Request Quote |
| HB-25 | 0.1 | 0.512 | 0.5 | 20 | 1.30:1 | 0.55 | 5 | 200 | 9-10 Weeks | N/A | Request Quote |
| HB-25-2K | 0.1 | 0.5 | 0.35 | 18 | 1.30:1 | 0.6 | 3 | 2000 | 9-10 Weeks | N/A | Request Quote |
| HCD-18 | 0.1 | 0.5 | 0.8 | 25 | 1.40:1 | 0.4 | 5 | 100 | 9-10 Weeks | N/A | Request Quote |
| HCD-19 | 0.1 | 0.5 | 1 | 20 | 1.35:1 | 0.3 | 5 | 200 | 9-10 Weeks | N/A | Request Quote |
| HCD-20 | 0.1 | 1 | 1.3 | 20 | 1.30:1 | 0.4 | 5 | 50 | 9-10 Weeks | N/A | Request Quote |
| JL-7 | 0.1 | 0.2 | 1.2 | 20 | 1.35:1 | 0.75 | 3 | 1 | 4-6 Weeks | N/A | Request Quote |
| JL-20 | 0.1 | 0.5 | 1.2 | 25 | 1.30:1 | 0.3 | 3 | 1 | 4-6 Weeks | N/A | Request Quote |
| JL-7/NF | 0.1 | 0.2 | 1.2 | 20 | 1.30:1 | 0.75 | 3 | 1 | 4-6 Weeks | N/A | Request Quote |
| JL-20/NF | 0.1 | 0.5 | 1.2 | 25 | 1.50:1 | 0.4 | 3 | 1 | 4-6 Weeks | N/A | Request Quote |
| HL-10 | 0.12 | 0.12 | 0.5 | 20 | 1.20:1 | 0.3 | 2.5 | 1 | 4-6 Weeks | N/A | Request Quote |
| HL-10/NF | 0.12 | 0.12 | 0.5 | 20 | 1.20:1 | 0.3 | 2.5 | 1 | 4-6 Weeks | N/A | Request Quote |
| HL-11 | 0.14 | 0.14 | 0.5 | 20 | 1.20:1 | 0.3 | 2.5 | 1 | 4-6 Weeks | N/A | Request Quote |
| HL-11/NF | 0.14 | 0.14 | 0.5 | 20 | 1.20:1 | 0.3 | 2.5 | 1 | 4-6 Weeks | N/A | Request Quote |
| HL-12 | 0.2 | 0.2 | 0.5 | 20 | 1.30:1 | 0.5 | 3 | 1 | 4-6 Weeks | N/A | Request Quote |
| HL-12/NF | 0.2 | 0.2 | 0.5 | 20 | 1.30:1 | 0.5 | 3 | 1 | 4-6 Weeks | N/A | Request Quote |
| HB-70 | 0.2 | 0.5 | 0.2 | 20 | 1.30:1 | 0.3 | 5 | 1000 | 9-10 Weeks | N/A | Request Quote |
| HB-94 | 0.2 | 2 | N/A | 16 | 1.40:1 | 0.3 | 5 | 100 | 6-8 Weeks | N/A | Request Quote |
| HCD-22 | 0.2 | 0.4 | 0.2 | 20 | 1.40:1 | 0.2 | 5 | 400 | 9-10 Weeks | N/A | Request Quote |
| HCD-23 | 0.2 | 0.4 | 0.3 | 20 | 1.30:1 | 0.5 | 5 | 2,500 | 9-10 Weeks | N/A | Request Quote |
| HCD-25 | 0.2 | 1 | 0.3 | 20 | 1.30:1 | 0.35 | 5 | 750 | 9-10 Weeks | N/A | Request Quote |
| HCD-25-20 | 0.2 | 1 | 1.2 | 20 | 1.40:1 | 0.4 | 5 | 20 | 9-10 Weeks | N/A | Request Quote |
| HJ-1 | 0.2 | 0.4 | 0.2 | 20 | 1.40:1 | 0.5 | 5 | 200 | Stock - 1 Week | N/A | Request Quote |
| JL-8 | 0.2 | 0.4 | 1.5 | 20 | 1.50:1 | 1 | 4 | 1 | 4-6 Weeks | N/A | Request Quote |
| JL-8/NF | 0.2 | 0.4 | 1.5 | 20 | 1.30:1 | 1 | 4 | 1 | 4-6 Weeks | N/A | Request Quote |
| HB-71 | 0.225 | 0.41 | 0.2 | 20 | 1.30:1 | 0.3 | 5 | 1200 | 9-10 Weeks | N/A | Request Quote |
| HL-13 | 0.3 | 0.3 | 0.5 | 20 | 1.30:1 | 0.5 | 3 | 1 | 4-6 Weeks | N/A | Request Quote |
| HL-13/NF | 0.3 | 0.3 | 0.5 | 20 | 1.30:1 | 0.5 | 3 | 1 | 4-6 Weeks | N/A | Request Quote |
| HB-21 | 0.4 | 4.5 | 1.5 | 20 | 1.35:1 | 0.6 | 5 | 30 | 9-10 Weeks | N/A | Request Quote |
| HB-21/NF | 0.4 | 4.5 | 1.5 | 20 | 1.35:1 | 0.6 | 5 | 20 | 9-10 Weeks | N/A | Request Quote |
Full Product Line Specifications
| Parameter | Range / Options |
|---|---|
| Phase Types | 90 degree (quadrature), 180 degree (rat race) |
| Frequency Range | DC / 0.00001 GHz to 60.0 GHz (series-dependent) |
| Power Handling | 1 W to 2,000 W average (series-dependent) |
| Coupling | 3 dB equal split standard |
| Insertion Loss | Low loss across all series; see individual subcategory datasheets |
| Amplitude Balance | As tight as +/-0.5 dB across rated bandwidth |
| Phase Balance | As tight as +/-2 degrees across rated bandwidth |
| Port-to-Port Isolation | Typically 20 dB and above |
| VSWR | As low as 1.20:1 on select models |
| Construction Technologies | Stripline, lumped element |
| Connector Options | SMA Female, Type N; tab connections on select models |
| Series Available | HB/HBX (90 degree Stripline), HL (90 degree Lumped Element), JL (180 degree Lumped Element), HJ (180 degree Coupler), HCD (180 degree Combiner/Divider) |
| Custom Design | Available. Contact MCLI engineering for non-standard requirements. |
Where MCLI Hybrid Couplers Are Used
| Parameter | Range / Options |
|---|---|
| Phase Types | 90 degree (quadrature), 180 degree (rat race) |
| Frequency Range | DC / 0.00001 GHz to 60.0 GHz (series-dependent) |
| Power Handling | 1 W to 2,000 W average (series-dependent) |
| Coupling | 3 dB equal split standard |
| Insertion Loss | Low loss across all series; see individual subcategory datasheets |
| Amplitude Balance | As tight as +/-0.5 dB across rated bandwidth |
| Phase Balance | As tight as +/-2 degrees across rated bandwidth |
| Port-to-Port Isolation | Typically 20 dB and above |
| VSWR | As low as 1.20:1 on select models |
| Construction Technologies | Stripline, lumped element |
| Connector Options | SMA Female, Type N; tab connections on select models |
| Series Available | HB/HBX (90 degree Stripline), HL (90 degree Lumped Element), JL (180 degree Lumped Element), HJ (180 degree Coupler), HCD (180 degree Combiner/Divider) |
| Custom Design | Available. Contact MCLI engineering for non-standard requirements. |
Balanced Amplifier Designs
A balanced amplifier uses two identical amplifiers combined with a pair of 90 degree hybrid couplers, one at the input and one at the output. The input hybrid splits the signal into two equal-amplitude, 90-degree-phase-shifted paths that feed each amplifier. The output hybrid recombines the two amplified signals back into a single output.
The primary advantage of this topology is impedance matching: reflections from each amplifier return to the input hybrid where they cancel at the input port and are absorbed at the isolated port, preventing mismatch from affecting the source. The result is a combined amplifier with better input and output return loss than either amplifier achieves individually, along with higher total output power.
Antenna Beam Forming Networks and Butler Matrices
Phased array antennas use hybrid couplers as the fundamental building block in Butler matrix beam forming networks. A Butler matrix uses a combination of 90 degree hybrid couplers and fixed phase shifters to produce orthogonal beams from a multi-element antenna array.
Each input port of the matrix drives a different beam direction. MCLI’s stripline hybrid series covers the frequency ranges used in airborne and ground-based phased array radar systems, and the high power HJ series handles the elevated power levels present in high-power transmit beam forming networks.
Image Rejection and Balanced Mixers
Quadrature hybrids are the key component in image rejection and single-sideband mixers. By driving two mixers with the same RF signal but 90 degrees phase-shifted LO signals, and then recombining the IF outputs with another 90 degree hybrid, the image frequency is cancelled while the desired signal adds constructively.
The degree of image rejection achieved depends directly on the amplitude and phase balance of the hybrid couplers used. Tighter balance produces greater image rejection. MCLI’s tight amplitude balance specifications, as tight as +/-0.5 dB, and phase balance, as tight as +/-2 degrees, support high image rejection ratios in both commercial and defense receiver designs.
Reflection Phase Shifters
A reflection phase shifter uses a 90 degree hybrid coupler with two identical variable reactances, such as varactor diodes or switched capacitors, connected to the two output ports. Signals reflected from those reactances recombine at the hybrid’s isolated port with a phase shift that depends on the reactance value.
Because both output ports see equal-amplitude signals from the hybrid, the combined reflection adds coherently and the reflected signal appears entirely at the isolated port rather than the input port. This technique generates a continuous or switched phase shift with low insertion loss and is widely used in phased array transmit and receive modules.
Signal Splitting, Combining, and Diplexer Applications
Beyond their role in complex circuit topologies, hybrid couplers serve as straightforward 3 dB splitters and combiners in applications where the 90 degree or 180 degree phase relationship between ports is useful for reducing interaction between combined signal paths.
The 180 degree hybrid’s ability to sum two in-phase signals or cancel two out-of-phase signals at its output ports makes it useful in diplexer designs, interference cancellation circuits, and differential signal processing applications.
90 Degree vs. 180 Degree: Choosing the Right Hybrid
| Feature | 90 Degree Hybrid (Quadrature) | 180 Degree Hybrid (Rat Race) |
|---|---|---|
| Output Phase Relationship | 90 degrees between output ports | 0 degrees or 180 degrees depending on input port used |
| Also Known As | Quadrature hybrid, branch line coupler | Rat race coupler, hybrid ring |
| Bandwidth | Broad; octave and multi-octave models available | Narrower than 90 degree designs at equivalent construction |
| Primary Applications | Balanced amplifiers, image rejection mixers, Butler matrix, reflection phase shifters | In-phase and out-of-phase signal combining, diplexers, differential circuits |
| MCLI Series | HB/HBX (Stripline), HL (Lumped Element) | JL (Lumped Element), HJ (Coupler), HCD (Combiner/Divider) |
Frequently Asked Questions: 90° & 180° Hybrid Couplers
What Is the Difference Between a 90 Degree and a 180 Degree Hybrid Coupler?
Both are four-port 3 dB devices that split input power equally between two output ports. The difference is the phase relationship at those output ports. A 90 degree hybrid delivers equal-amplitude outputs with exactly 90 degrees of phase difference between them, regardless of which port is driven. A 180 degree hybrid delivers equal-amplitude outputs that are either in phase or 180 degrees out of phase depending on which input port receives the signal. The choice between them depends on the phase relationship your application requires at the combined or split ports.
What Is a Quadrature Hybrid and Why Is It Used in Balanced Amplifiers?
A quadrature hybrid is another name for a 90 degree hybrid coupler. In a balanced amplifier, two quadrature hybrids are used: one at the input to split the signal into two 90-degree-shifted paths, and one at the output to recombine the amplified signals. Reflections from each amplifier return to the input hybrid where they arrive 180 degrees out of phase and cancel at the input port, routing to the isolated port instead. This cancellation means the balanced amplifier presents a good impedance match at its input port even if the individual amplifiers have poor return loss.
What Are Amplitude Balance and Phase Balance, and How Do They Affect System Performance?
Amplitude balance is the difference in signal level between the two output ports, expressed in dB. Phase balance is the deviation of the actual phase difference between output ports from the ideal 90 or 180 degrees, expressed in degrees. In an image rejection mixer, amplitude and phase imbalance directly limit the achievable image rejection ratio. In a balanced amplifier, amplitude imbalance drives one amplifier harder than the other, reducing the benefit of combining. In a Butler matrix, phase imbalance degrades beam orthogonality and increases sidelobe levels. Tighter balance specifications produce better performance in all of these applications.
Can Hybrid Couplers Handle High Power Levels?
Yes. MCLI’s HJ series coupler covers 0.0001 to 50 GHz at average power levels from 10 to 500 watts, and select models reach 2,000 watts. Power handling in a hybrid coupler depends on the construction technology, connector type, and the degree of mismatch on the output ports. When both output ports are terminated or driven with matched impedances, power is distributed evenly and each element handles half the total power. Mismatch on an output port sends reflected power back into the coupler, increasing internal dissipation above the rated average. MCLI engineering can advise on appropriate derating for specific power and mismatch conditions.
What Is a Rat Race Coupler and When Should I Use One Instead of a 90 Degree Hybrid?
A rat race coupler is a 180 degree hybrid. Its name comes from its ring-shaped transmission line construction, which has a circumference of 1.5 wavelengths with ports spaced at quarter-wavelength intervals. Use a rat race when you need to add two signals in phase at one output port while rejecting their difference, or subtract two signals by using the 180 degree port relationship. It is also used to produce two equal-amplitude, out-of-phase signals from a single input. Use a 90 degree hybrid when your application needs quadrature phase splitting, such as in balanced amplifiers, image rejection mixers, or reflection phase shifters.
How Do I Choose Between Stripline and Lumped Element Construction?
Stripline hybrids use quarter-wavelength transmission line sections, which makes them well-suited for frequencies above 1 GHz where the physical dimensions of those sections are practical. MCLI’s HB/HBX stripline series covers 0.02 to 60 GHz. Lumped element hybrids replace the transmission line sections with discrete inductors and capacitors, making them compact and practical at frequencies below 1.5 GHz where stripline quarter-wave sections would be physically large. MCLI’s HL and JL lumped element series cover down to 0.01 GHz and 0.00001 GHz respectively. For applications below 1 GHz or where small form factor is a priority, lumped element is the right choice.
Does MCLI Offer Custom Hybrid Couplers for Non-Standard Frequencies or Power Levels?
Yes. MCLI designs custom 90 degree and 180 degree hybrid couplers for frequency ranges, power levels, connector types, and physical form factors outside the standard catalog. Custom designs are available for MIL-spec environmental requirements. Contact MCLI engineering with your specifications to start a custom design inquiry.