No abstract

No abstract

We have fabricated a 2 GHz 12-pole superconducting microstrip line filter and a 2-pole electrically tunable filter using interdigital electrodes and dielectric film. The change of the dielectric constant of a SrTi03 film, stacked on the filter, by applying a bias voltage between the electrodes leads to the tunability. The range of the center frequency modulation was 13 MHz (0.7 %) at 60 K, 75 kV/cm. The microwave frequency response was improved by modification of the electrode structure. This tuning method is considered to be promising in that individual resonance elements in multi-pole filters can be tuned independently.

Research a n d D e v e l o p m e n t C e n t e r , T o s h i b a C o r p o r a t i o n 1 K o m u k a i T o s h i b a c h o , S a i w a i -k u , K a w a s a k i -s h i 2 1 0 , J a p a n ABSTRACT A one-dimensional self-consistent particle simulator was d e v e l o p e d f o r ( A l G a ) A s / G a A s h e t e r o j u n c t i o n b i p o l a r transistors (HBTs) to investigate how far the device performance can be improved by positively utilizing non-equilibrium electron transport phenomena under a heavily doped base condition. Computation was thus carried out for HBTs with various c a t e g o r i e s o f b a s e a n d c o l l e c t o r s t r u c t u r e s . T h e e l e c t r o n transport mechanisms are discussed in detail according to the results in conjunction with the Feduction in base-to-collector transit time.

No abstract