1. Microwave Update 2010, Cerritos, CA
Modifying a 10 GHz Dielectric Resonant Oscillator for Amateur Radio Use
Brian Yee, W6BY
Microwave Update 2010, Cerritos, CA

2. Motivation
Wanted an alternative to “brick” oscillators, as an experiment
Eliminate DC-DC converters, if possible
Use newer technology
Use parts at hand in the junkbox
Reduce power consumption
Smaller packaging
Needed dual outputs at MHz in order to build a dual-band 10/24 GHz transverter
Wanted single 10 MHz reference input

3. What was available?
Found a DMC MHz Dielectric Resonant oscillator in the junkbox ( )
Single +8.4 V supply, lock indicator and loop monitor
Internal (but not so accurate) 100 MHz ovenized crystal oscillator
Pretty good phase noise
Would need extensive modification and new crystal

4. DRO Basics
Consists of a ceramic puck made of material with a high dielectric constant
Resonant frequency determined by physical size and shape (usually cylindrical)
Will radiate if not shielded (this property used to tune frequency or make antennas)

5. DRO Basics (cont’d)
DRO puck used as the feedback element in oscillators
Stub with varicap is used to provide fine tuning
Coarse tuning via tuning screw
Circuit Q of over 10,000 is possible
Light weight, rugged
Circuit and picture from Siemens Semiconductor application note No. 002

6. Unmodified DMC DRO Unit

7. Unmodified DMC Unit Internal Architecture
Dielectric Resonant Oscillator
Dual outputs
10,192 MHz
Tune Voltage
Div 8
1274 MHz
26 MHz
Loop Filter
X 12
F Det f
1248 MHz
26 MHz
104 MHz
XTAL
Div 4

8. “The Plan” Use Peregrine PE3341 for synthesizer
Has onboard flash register so no microcontroller necessary
Needs a $pecial programming tool
TSSOP package discontinued, now only MLFs available
Use Hittite HMC363-S8G divide by 8 prescaler
Linear regulators for clean power rails
Autocad for mechanical layout
Protel for schematic capture and PCB layout
All done on 1/32” FR-4, using MG Chemical positive resist presensitized copper clad boards

9. W6BY PE3341 Design Div 8 Buffer PE3341 Synth
Dielectric Resonant Oscillator
Dual outputs
10,224 MHz
Tune Voltage
Div 8
1278 MHz
Loop Filter
Buffer f
PE3341 Synth
MHz OCXO

10. Peregrine Software

11. Circuit boards: PLL & Prescaler
10 GHz RF
Prescaler
Loop Filter
Synthesizer IC

12. Circuit Boards: Input Buffer & Regulators
10 MHz Input
Main Regulator
10 MHz MMIC Buffer

13. Assembly: Top View DRO Oscillator RF Output Buffers
RF Sampler & Buffer
PLL Board

14. Assembly: Bottom View Existing Power Regulator 10 MHz Input
New Regulator Board

15. Before/After

16. Results: Spectrum Analyzer Plots
Span 200 MHz
Span 500 MHz

17. Results: Spectrum Analyzer Plots
Phase Noise Plot
Span 10 MHz
(Spurs from power supply)

18. Lessons Learned, future projects
There are lots of things to be learned by just trying something
The junk box is your friend – keep feeding it
Next project possibilities:
new-generation synthesizer IC’s
YIG
CRO