Embedded Antenna for Metallic Handheld Communication Devices

Abstract

Abstract-In this study, a quad-band folded slot antenna with a monopole feed line embedded in a conductive housing structure (the LCD bracket of a mobile phone) is proposed. The performance of the proposed antenna is evaluated through simulation and measurement, demonstrating that it can provide total radiation efficiencies of more than 40% in the EGSM900, DCS, PCS, and WCDMA1 bands. Over these four bands, the total radiated power (TRP) of a prototype mobile phone using the antenna is 28.5, 27.1, 27.5, and 21 dBm, respectively, while the total isotropic sensitivity (TIS) is 102.7, 104.3, 103.8, and 107.3 dBm, respectively; all of these values satisfy Cellular Telecommunication and Internet Association (CTIA) requirements for over-the-area-(OTA) testing standards. The radiation performance of the proposed antenna in the calling mode is tested and shown to be within satisfactory limits; similarly, the specific absorption rates (SARs) of the prototype mobile phone are also found to be within standard SAR limits.

Ambipolar suppression of superconductivity by ionic gating in optimally doped BaFe2(As,P)2 ultrathin films

“…This marked suppression and broadening of the resistive transition with decreasing thickness could be either an intrinsic feature of Ba-122 thin films, as in the case of YBa 2 Cu 3 O 7−δ [30,31], or instead be due to the specific growth conditions of our samples. The first interpretation can be supported by the observation of a suppressed and broadened transition in Ba(Fe,Co) 2 As 2 /STO superlattices when the thickness of the Ba-122 layers approaches ∼ 12 nm [32], as well as the absence of SC in Ba(Fe,Co) 2 As 2 films less than 3 nm thick [33]. The second interpretation can instead be associated with the different surface morphology between our 10 nm thick film and the 50 nm thick film of Ref.…”