RF design of compact X-band waveguide components Alexej Grudiev, CERN 18/05/2016

Motivation CLIC is compact and needs compact solutions With arrival of Toshiba 6MW klystron X-band RF unit becomes more compact -> need for more compact RF components Combining these more compact RF units requires more RF component -> need for more compact RF components Furthermore scaling proposed solutions to C- and S-band is straightforward and results in smaller size and cost components at C- and S-band 18/05/2016, A. Grudiev

Compact E-plane hybrids: E-Hybrids E-hybrid for CLIC SAS (2010) E-hybrid return (2016) Hybrid Design goal functions: Old |S13|2=0.5; |S14|2=0.5; |arg{S14}-arg{S13}|=90degree ------------------------------------------------- New |Re{S13}Im{S14}+Im{S13}Re{S14}|= Conversion = 0.5 1 2 1 4 2 3 4 3 E-hybrid CLIC E-hybrid return Bandwidth at -30 dB [MHz] S11 187 312 S12 311 1-2Conv - 220 Max. Surface Fields Pin=1W Pin=100MW E [MV/m] 0.0034 34 0.0043 43 H [kA/m] 0.0091 91 0.0076 76 S [MW/mm2] 1.1e-8 1.1 1.0e-8 1 18/05/2016, A. Grudiev

Compact E-plane circular TE11 rotating mode launcher (E-Rotator) 3 2 1 Design goal function: Conversion = 0.5 = |Re{S13x}Im{S13y}+Im{S13x}Re{S13y}| Bandwidth at -30 dB [MHz] Max Surface Fields at Pin=1W at Pin=100MW S11 78 E [MV/m] 0.0051 51 S12 65 H [kA/m] 0.018 180 1-2Conversion 50 S [MW/mm^2] 2e-8 2 18/05/2016, A. Grudiev

Compact Movable Shorts based on Circular Choke Circular Waveguide D16mm WR90 20 degree/mm Parasitic transmission coaxial port isolation 18/05/2016, A. Grudiev

Compact Phase Shifter for WR90 ~20 degree/mm of ShortL 18/05/2016, A. Grudiev

Electric field at 1W and S-pars for different position of the movable Short Reflection bandwidth Is the same as rotator 1W 1W ShortL Reflection < -40 dB Parasitic transmission to Movable Short <-65dB 18/05/2016, A. Grudiev

Adjustable power splitter Reflection and transmission to vacuum pumping port Vac. pump 18/05/2016, A. Grudiev

Variable power splitter Reflection and transmission to vacuum pumping port Vac. pump 4 3 1 2 18/05/2016, A. Grudiev

Variable polarization circular TE11 mode launcher Phase difference between port 1 and port 2: 0 degree -> vertical polarization 180 degree -> horizontal polarization Vacuum pumping port RF Loads E-Hybrid Variable Phase Shifter Deflecting Structure E-Rotator E-Rotator 18/05/2016, A. Grudiev

Compact X-band RF load One half cut away Water cooling Vacuum, CF WR90, RF Flange-to-flange length ~250mm Material Ti6V4Al alloy, cond=600000S/m additive manufacturing 18/05/2016, A. Grudiev

Reflections versus roughness, Ra=0 – 50um Roughness > 10um is expected 18/05/2016, A. Grudiev

EM fields, Pin=2W, 12GHz, Ra=0 Pin Esurf_max Hsurf_max Sc_max 2W 11 kV/m 24 A/m 0.024 MW/m2 m Pin Esurf_max Hsurf_max Sc_max 50MW 55 MV/m 120 kA/m 0.6 MW/mm2 Sc [W/m2] 18/05/2016, A. Grudiev

H-field distribution versus Ra for Pin=2W Ra=0.5um Ra=1um Ra=5um Ra=50um 18/05/2016, A. Grudiev