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

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 10224 MHz in order to build a dual-band 10/24 GHz transverter Wanted single 10 MHz reference input

What was available? Found a DMC 10250 MHz Dielectric Resonant oscillator in the junkbox (131-1145-6-003) 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

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)

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

Unmodified DMC DRO Unit

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

“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

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 10.000 MHz OCXO

Peregrine Software

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

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

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

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

Before/After

Results: Spectrum Analyzer Plots Span 200 MHz Span 500 MHz

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

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