120,321 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
Dark sector interaction: a remedy of the tensions between CMB and LSS data
The well-known tensions on the cosmological parameters and
within the CDM cosmology shown by the Planck-CMB and LSS data are
possibly due to the systematics in the data or our ignorance of some new
physics beyond the CDM model. In this letter, we focus on the second
possibility, and investigate a minimal extension of the CDM model by
allowing a coupling between its dark sector components (dark energy and dark
matter). We analyze this scenario with Planck-CMB, KiDS and HST data, and find
that the and tensions disappear at 68\% CL. In the joint
analyzes with Planck, HST and KiDS data, we find non-zero coupling in the dark
sector up to 99\% CL. Thus, we find a strong statistical support from the
observational data for an interaction in the dark sector of the Universe while
solving the and tensions simultaneously.Comment: 5 pages, 3 figure
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
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