Dual 20 dB Microstrip Coupler high directivity
Budget: €50 – €100 EUR
I need a compact dual-directional microstrip coupler (6 ports in total) laid out on 0.6 mm FR-4 that will let me read forward and reverse power from 30 MHz right up to 1 GHz. The target coupling is a clean, flat 20 dB across that span; directivity and return loss just have to be good enough for reliable watt-meter style measurements, not laboratory-grade calibration. all ports are 50 ohms
Because the board will live inside existing test gear, the stack-up is fixed (standard 0.6 mm FR-4, copper on both sides) and space is tight, maximum dimension are 30mm length, 18 mm width connector excluded, so I’m after an efficient topology rather than a textbook λ/4 directional coupler that only really behaves above a few hundred MHz. Feel free to get creative with multi-section, tight-coupled lines or lumped-element compensation as long as it stays single-layer microstrip with ground on the reverse and can be fabricated by any budget PCB house.
Design needs to resist at least 100W of power even with high VSW on main port. Directivity of at least 35 dB to help me reading on the other port.
Once the design is done, I will verify the behaviour with produced hardware.
When you deliver, I need:
• working layout and Gerbers ready for manufacture
• the original design files and EM simulations (Keysight ADS, CST, HFSS or similar—whatever you used) showing S-parameters from 30 MHz-1 GHz
• a short note on expected insertion loss, isolation and directivity, plus any tuning tips in case real-world FR-4 permittivity drifts
If you have already tamed FR-4 for wideband couplers, I would love to see an example plot or photo of previous work to speed up selection.
Because the board will live inside existing test gear, the stack-up is fixed (standard 0.6 mm FR-4, copper on both sides) and space is tight, maximum dimension are 30mm length, 18 mm width connector excluded, so I’m after an efficient topology rather than a textbook λ/4 directional coupler that only really behaves above a few hundred MHz. Feel free to get creative with multi-section, tight-coupled lines or lumped-element compensation as long as it stays single-layer microstrip with ground on the reverse and can be fabricated by any budget PCB house.
Design needs to resist at least 100W of power even with high VSW on main port. Directivity of at least 35 dB to help me reading on the other port.
Once the design is done, I will verify the behaviour with produced hardware.
When you deliver, I need:
• working layout and Gerbers ready for manufacture
• the original design files and EM simulations (Keysight ADS, CST, HFSS or similar—whatever you used) showing S-parameters from 30 MHz-1 GHz
• a short note on expected insertion loss, isolation and directivity, plus any tuning tips in case real-world FR-4 permittivity drifts
If you have already tamed FR-4 for wideband couplers, I would love to see an example plot or photo of previous work to speed up selection.