119,919 research outputs found
Design of a New Step-like Frame FBAR for Suppression of Spurious Resonances
Film bulk acoustic wave resonators (FBARs) are of great interest for wireless applications due to its inherent advantages at microwave frequencies. However, the presence of spurious modes near the main resonance degrades the performance of resonators and requires development of new methods to suppress such unwanted modes. Different techniques are used to suppress these spurious modes. In this paper, we present design of a new step-like frame structure film bulk acoustic wave resonator operating near 1.5 GHz. The simulated results are compared with simple frame-like structure. The spurious resonances are eliminated effectively and smooth pass band is obtained with effective coupling coefficient of 5.68% and quality factor of 1800. The equivalent electrical mBVD model of the FBAR based on impedance response is also presented. These highly smooth phase response and passband skirt steepness resonators are most demanding for the design of low cost, small size and high performance filters, duplexers and oscillators for wireless systems
On Rational Sets in Euclidean Spaces and Spheres
IFor a positive rational , we define the concept of an -elliptic and an
-hyperbolic rational set in a metric space. In this article we examine the
existence of (i) dense and (ii) infinite -hyperbolic and -ellitpic
rationals subsets of the real line and unit circle. For the case of a circle,
we prove that the existence of such sets depends on the positivity of ranks of
certain associated elliptic curves. We also determine the closures of such sets
which are maximal in case they are not dense. In higher dimensions, we show the
existence of -ellitpic and -hyperbolic rational infinite sets in unit
spheres and Euclidean spaces for certain values of which satisfy a weaker
condition regarding the existence of elements of order more than two, than the
positivity of the ranks of the same associated elliptic curves. We also
determine their closures. A subset of the -dimensional unit sphere
has an antipodal pair if both for some . In this article,
we prove that there does not exist a dense rational set which
has an antipodal pair by assuming Bombieri-Lang Conjecture for surfaces of
general type. We actually show that the existence of such a dense rational set
in is equivalent to the existence of a dense -hyperbolic rational set
in which is further equivalent to the existence of a dense 1-elliptic
rational set in the Euclidean space .Comment: 20 page
You Manage What You Measure: Using Mobile Phones to Strengthen Outcome Monitoring in Rural Sanitation
This paper addresses the sanitation challenge in India, where it is home to the majority of people defecating in the open in the world and also one of the top rapidly growing emerging economies. The paper focuses on the need for a reliable and timely monitoring system to ensure investments in sanitation lead to commensurate outcomes
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