High peak and high average power transmit receive switch for thermal magnetic resonance or radiofrequency heating applications.


Yiyi Ji¹, Werner Hoffmann², Michal Pham¹, Alexander E. Dunn³, Haopeng Han¹, Celal Özerdem¹, Helmar Waiczies4, Michael Rohloff¹, Beate Endemann¹, Cyrille Boyer³, May Lim³, Thoralf Niendorf1,5, Lukas Winter2

Estimated cost

Total price (material costs):



v1.0, released as Open Source Hardware (CERN OHL v1.2)

To study the role of temperature in biological systems, diagnostic contrasts and thermal therapies, RF pulses for MR spin excitation can be deliberately used to apply a thermal stimulus. This application requires dedicated transmit/receive (Tx/Rx) switches that support high peak powers for MRI and high average powers for RF heating. To meet this goal, we propose a high‐performance Tx/Rx switch based on positive‐intrinsic‐negative diodes and quarter‐wavelength (λ/4) stubs. The λ/4 stubs in the proposed Tx/Rx switch design route the transmitted RF signal directly to the RF coil/antenna without passing through any electronic components (e.g., positive‐intrinsic‐negative diodes).


Isolation (transmission port – reception port): -56.3dB
Insertion loss (transmission port – RF coil/antenna): -0.35dB

Isolation (transmission port – reception port): -57.6dB
Insertion loss (RF coil/antenna – Rx): -0.21dB

MR Imaging performed at 3.9kW peak power
RF heating performed at 120W average power

Assembly instructions, schematics, partlist etc. can be found on the github page:



1Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany

2Physikalisch Technische Bundesanstalt, Berlin, Germany

3School of Chemical Engineering, The University of New South Wales, Sydney, Australia

4MRI.TOOLS GmbH, Berlin, Germany

5Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany