Design of a stable dielectric resonator oscillator

inż. Andrzej Stefański mgr. inż. Krzysztof Czuba

dr inż. Krzysztof Antoszkiewicz

Instytut Systemów Elektronicznych PW

Design of a stable dielectric resonator oscillatorA. Stefański, ISE, PW 2

Outline

• Objective and specifications

• Dielectric resonator

• Problems to solve

• Current project status

• Future plans

Design of a stable dielectric resonator oscillatorA. Stefański, ISE, PW 3

Objective• Low phase noise Dielectric Resonator

Oscilator (DRO) is needed for the phase reference system for the UVFEL/XFEL projects

• DRO will be synchronized with the Master Oscillator

• DR based oscillators offer very high noise performance but generator design is very difficult

Design of a stable dielectric resonator oscillatorA. Stefański, ISE, PW 4

Specifications

• Output freq. : 1299.9996 MHz

• Voltage controlled input

• Output power : 10 dBm

• Harmonics : < -25 dBc

• Sub-harmonics: < -60 dBc

• Spurious : < -80 dBc

• Extremely low phase noise – next page

Design of a stable dielectric resonator oscillatorA. Stefański, ISE, PW 5

-180

-160

-140

-120

-100

-80

-60

-40

-20

0

Distance from carrier frequency [Hz]

Ph

ase

no

ise

[dB

c/H

z]

Limit -60 -80 -105 -135 -155 -150

10 100 1k 10k 100k 1M

Required phase noise level

Design of a stable dielectric resonator oscillatorA. Stefański, ISE, PW 6

Dielectric Resonator

Design of a stable dielectric resonator oscillatorA. Stefański, ISE, PW 7

Design issues/problems

• Selection of low-noise transistor• Oscillator circuit design• Tuning method selection• Minimizing noise from tuning circuit• Selection of DR coupling method – oscillation and

output signal• Mechanical design: oscillator cavity, DR fixture –

significantly affect oscillator performance

Design of a stable dielectric resonator oscillatorA. Stefański, ISE, PW 8

Recent development

Design of a stable dielectric resonator oscillatorA. Stefański, ISE, PW 9

Current project status

• Analysis of existing design, found ways for oscillator improvement

• 3D electromagnetic field simulations in progress. Objective – find optimum coupling method, estimate quality factor and extract S-parameters for electronic circuit simulations

• 3D model created and first simulation results obtained

Design of a stable dielectric resonator oscillatorA. Stefański, ISE, PW 10

Design of a stable dielectric resonator oscillatorA. Stefański, ISE, PW 11

Design of a stable dielectric resonator oscillatorA. Stefański, ISE, PW 12

Design of a stable dielectric resonator oscillatorA. Stefański, ISE, PW 13

Future plans

• Cavity optimization– 3D simulations– S-parameters extraction

• Circuit optimization– Find transistor with best noise performance– Apply it to optimal circuit

• Make project and build model• Measurements

Thank you