RF design of compact Xband waveguide components Alexej

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 6 MW 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 Cand S-band 18/05/2016, A. Grudiev

Compact E-plane hybrids: E-Hybrids E-hybrid for CLIC SAS (2010) 1 2 4 3 18/05/2016, A. Grudiev Hybrid Design goal functions: Old |S 13|2=0. 5; |S 14|2=0. 5; |arg{S 14}-arg{S 13}|=90 degree ------------------------New |Re{S 13}Im{S 14}+Im{S 13}Re{S 14}|= Conversion = 0. 5 E-hybrid return (2016) 1 4 2 3 E-hybrid CLIC E-hybrid return Bandwidth at -30 d. B [MHz] S 11 187 312 S 12 187 311 1 -2 Conv - 220 Max. Surface Fields Pin=1 W Pin=100 MW E [MV/m] 0. 0034 34 0. 0043 43 H [k. A/m] 0. 0091 91 0. 0076 76 S [MW/mm 2] 1. 1 e-8 1. 1 1. 0 e-8 1

Compact E-plane circular TE 11 rotating mode launcher (E-Rotator) 1 2 3 Design goal function: Conversion = 0. 5 = |Re{S 13 x}Im{S 13 y}+Im{S 13 x}Re{S 13 y}| 18/05/2016, A. Grudiev Bandwidth at -30 d. B [MHz] Max Surface Fields at Pin=1 W at Pin=100 MW S 11 78 E [MV/m] 0. 0051 51 S 12 65 H [k. A/m] 0. 018 180 1 -2 Conversion 50 S [MW/mm^2] 2 e-8 2

Compact Movable Shorts based on Circular Choke Circular Waveguide D 16 mm WR 90 20 degree/mm Parasitic transmission coaxial port isolation 18/05/2016, A. Grudiev

Compact Phase Shifter for WR 90 ~20 degree/mm of Short. L 18/05/2016, A. Grudiev

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

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

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

Variable polarization circular TE 11 mode launcher Phase difference between port 1 and port 2: • 0 degree -> vertical polarization • 180 degree -> horizontal polarization Vacuum pumping port E-Hybrid RF Loads Variable Phase Shifter Deflecting Structure E-Rotator 18/05/2016, A. Grudiev E-Rotator

Compact X-band RF load One half cut away ling coo Water , WR 90 RF m, Vacuu ling o o c r Wate lang -to-f e g n a l F 0 mm ~25 h t g n e el Material Ti 6 V 4 Al alloy, cond=600000 S/m additive manufacturing 18/05/2016, A. Grudiev CF

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

EM fields, Pin=2 W, 12 GHz, Ra=0 m m Sc [W/m 2] 18/05/2016, A. Grudiev Pin Esurf_max Hsurf_max Sc_max 2 W 11 k. V/m 24 A/m 0. 024 MW/m 2 Pin Esurf_max Hsurf_max Sc_max 50 MW 55 MV/m 120 k. A/m 0. 6 MW/mm 2

H-field distribution versus Ra for Pin=2 W Ra=0. 5 um 18/05/2016, A. Grudiev Ra=1 um Ra=50 um