document: Improving the frequency stability of microwave oscillators by utilizing the dual-mode sapphire-loaded cavity resonator The design and experimental testing of a novel control circuit to stabilize the temperature of a sapphire-loaded cavity whispering gallery resonator-oscillator and improve its medium-term frequency stability is presented . Finite-element software was used to predict frequencies and quality factors of WGE/sub 7,0,0 / and the WGH/sub 9,0,0 / modes near 9 GHz , and separated in frequency by approximately 80 MHz . Calculations show that the novel temperature control circuits from the difference frequency can result in a frequency stability of better than one part in 10/sup 13 / at 270 K. Also , we present details on the best way to couple orthogonally to two modes of similar frequency but different polarization
doc_bio_tags: O O B I O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O B I O O O O B I O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O
extractive_keyphrases: microwave oscillators frequency stability difference frequency 9 ghz 270 k
abstractive_keyphrases: temperature control circuit dual-mode sapphire-loaded cavity resonator frequency standard temperature stabilisation whispering gallery resonator-oscillator finite-element analysis whispering gallery modes high-quality factor