A Medium Power Solid State Amplifier for V-Band
A solid state amplifier for the 54 to 58 GHz band is described. The amplifier uses two layer InP Gunn devices. Three stages of amplification provide an output power of 100 mW at a gain of 15 dB. The small signal gain is 30 dB; the noise figure is in the 15.5 to 16.5 dB range. The design of a broadband low-loss V-band circulator, which was used in the amplifier, is also described.
Influence of Non-Ideal Circulator Effects on Negative-Resistance Amplifier Design
It is well known that the non-ideal properties of a circulator (non-unity VSWR, non-zero insertion loss, finite isolation) have a marked effect on the design of single-stage and multi-stage negative-resistance amplifiers. These effects are due to the frequency dependence of the circulator parameters, the feedback associated with multiple reflections between circulator ports and terminations, and the possibility of spurious pass-bands in the circulator characteristics away from the desired operating frequency range. Noise degradation also occurs with a low-noise amplifier circuit.
Effects of diet on urine composition of cats with calcium oxalate urolithiasis.
Ten client-owned cats with calcium oxalate (CaOx) urolithiasis were evaluated to determine the effect of diet on urine CaOx saturation. Two dietary treatments were evaluated in each cat: the diet consumed just prior to urolith detection and a canned diet formulated to prevent CaOx uroliths. This study revealed that hypercalciuria is a consistent abnormality in cats with CaOx urolith formation. When urolith-forming cats consumed a diet formulated to prevent urolith formation, activity product ratios for CaOx (which estimate the degree to which urine is saturated with CaOx) were significantly lower. These results suggest that consumption of an appropriately formulated urolith-prevention diet will reduce recurrence of CaOx urolithiasis.