This letter presents an ultra-wideband low noise amplifier (LNA) using gallium-nitride (GaN) high-electron mobility transistors (HEMT) technology. A 3 dB bandwidth of 1-25 GHz with 13 dB peak power gain is achieved using a modified resistive-feedback topology. To obtain such a wide bandwidth, several bandwidth enhancement techniques are utilized. An inductor connected to the source of the input transistor ensures good input matching ( 11 9 dB) across the entire bandwidth. The shunt feedback loop and the inductive source degeneration minimize all the required inductor values. This GaN HEMT LNA is believed to have the widest bandwidth among all GaN HEMT monolithic microwave integrated circuit (MMIC) LNAs reported to date. With 3.3 dB minimum noise figure (F), 33.5 dBm maximum output-referred third-order intercept point (OIP3), 20 dBm maximum output-referred 1 dB compression point (Output P1 dB), this MMIC amplifier is comparable in performance to distributed amplifiers (DAs) but with significantly lower power consumption and smaller area. Index Terms-GaN, low noise amplifier (LNA), resistive feedback, wideband.
No abstract
The results of measurements of third-sound velocity in adsorbed superfluid helium films (1.12-1.85°K) are presented. It is found that the average superfluid fraction is nonvanishing at the superflow onset thickness and has a value about -J its bulk value. Possible reasons for a nonvanishing value are discussed. Healing lengths based on best fitting Ginzburg-Pitaevskii calculations are determined.
I n t h i s paper we discuss the recent advances i n a r e l a t i v e l y new c l a s s o f planar a c o u s t i c dev i c e s employing an a c o u s t i c wave which t r a v e l s j u s t below the surface. These waves a r e r e f e r r e d t o as shallow b u l k a c o u s t i c waves (SBAW's) o r as surface-skimming b u l k waves (SSBW's).I n the l a s t few years t h e r e has been a g r e a t deal o f a c t i v i t y i n t h i s area because o f the inherent advantages which SBAW devices possess over conventional b u l k and s u r f a c e a c o u s t i c wave devices. These devices can be employed as bandpass f i l t e r s and delay l i n e o s c i l l a t o r s , and thus can be incorporated i n t o a v a r i e t y o f s i g n a l processing systems. The mater i a l aspects, e q u i v a l e n t c i r c u i t , energy t r a p p i n g and devices development w i l l be presented i n t h i s overview. . I n t r o d u c t i o nShallow b u l k a c o u s t i c wave o r surface skimning b u l k wave devices u t i l i z e shear h o r i z o n t a l waves which propagate j u s t below the s u r f a c e o f t h e subs t r a t e . They were f i r s t r e p o r t e d by Yen, e t a l . and Lewis, e t a l . i n 1977.1*2 Since then t h e r e has been a g r e a t deal o f a c t i v i t y i n t h i s area because o f the inherent advantages t h a t they possess over conventional b u l k and surface a c o u s t i c wave devices.3-IB bandpass f i l t e r s and o s c i l l a t o r s , and thus can be incorporated i n t o a v a r i e t y o f s i g n a l processing systems. I n t h i s paper we w i l l discuss the recent advances of t h i s r e l a t i v e l y new c l a s s of planar b u l k a c o u s t i c wave devices. a r e the m a t e r i a l aspects, e q u i v a l e n t c i r c u i t , energy t r a p p i n g and devices development. These devices can be employed as Topics t o be discussed 2. SBAW M a t e r i a l s The important c r i t e r i a uses i n s e l e c t i n g SBAW/SSBW m a t e r i a l s a r e : 1. Large p i e z o e l e c t r i c c o u p l i n g t o shear h o r i z o n t a l wave. 2. Zero o r small p i e z o e l e c t r i c c o u p l i n g t o SAW and o t h e r b u l k waves. 3. Zero o r small beam s t e e r i n g b o t h on the surface and i n t o t h e b u l k . 4. Zero o r small temperature c o e f f i c i e n t o f d e l ay. Using these c r i t e r i a , we have concentrated on w i d e l y used SAW m a t e r i a l s : quartz, b e r l i n i t e , LiNbO and LiTaO 3 ' 3 For s i n g l y r o t a t e d Y-cut q u a r t z and b e r l i n i t e , the above c r i t e r i a a r e s a t i s f i e d w i t h wave propag a t i o n normal t o the X-axis. Here, the SAW and o t h e r b u l k waves c o u p l i n g c o e f f i c i e n t a r e i d e n t ic a l l y zero, so t h a t very spurious f r e e responses a r e obtained. I n a d d i t i o n , the shear h o r i z o n t a l wave s u f f e r s no beam s t e e r i n g on the surface, and f o r two small regions near AT-and BT-crystal, b o t h the temperature c o e f f i c i e n ...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.