Stub (electronics)

About: Stub (electronics) is a research topic. Over the lifetime, 8172 publications have been published within this topic receiving 75018 citations.

Compact frequency reconfigurable filtennas using varactor loaded T-shaped and H-shaped resonators for cognitive radio applications

Abstract: In this study, novel compact filtennas with large tunable frequency band are proposed for cognitive radio (CR) applications. Tunability is achieved by integrating a tunable T-shaped and H-shaped bandpass filter with a planar ultra-wideband monopole antenna. The T-shaped filter consists of a microstrip resonator loaded with a stub. The H-shaped filter is composed of two connected microstrip resonators. The proposed tuning technique for both filters is based on centrally loading the stub and the H-shaped with only a single varactor for miniaturisation. Increasing the varactor capacitance results in decreasing the even resonant mode of the resonator without affecting the dominant odd mode. Measurements results show that the proposed T-shaped and H-shaped filtennas are capable of tuning over a wide operating band of 1.68 and 1.73 GHz covering continuous bands for CR communication with 32.9% frequency tuning range (TR) from 4.26 to 5.94 GHz and with 36.7% frequency TR from 3.85 to 5.58 GHz, respectively. Moreover, the radiation patterns are stable over the operating frequency ranges. The frequency characteristics and radiation performance are successfully optimised using 3D full-wave electromagnetic simulator. The fabricated designs are measured for verification purposes. Good agreements are found between simulated and measured results.

Mechanical behavior of stirrup-confined rectangular CFT stub columns under axial compression

Abstract: This paper mainly presents a combined experimental, numerical and theoretical study on the mechanical behaviors of both conventional concrete-filled rectangular steel tubular stub columns (RST) and stirrup-confined concrete-filled rectangular steel tubular stub columns (SST) under compressive load. 16 RST stub columns and 16 SST stub columns were tested, with consideration of parameters including internal stirrup, concrete strength, and cross-sectional aspect ratio B/D. The failure patterns, bearing capacity, stiffness and ductility of specimens were analyzed based on the experimental results. A 3D finite element (FE) model was established for numerical simulation and parametric study to investigate the composite action among the steel tube, stirrups and the core concrete. The improvement of energy dissipation capability due to the stirrups confinement on the core concrete is also discussed. In addition, a unified theoretical formula to predicted ultimate bearing capacity for SST stub columns and RST stub columns subjected to compressive load was developed according to the superposition principle with rational simplification. It is shown that the proposed formula for these columns has a higher accuracy compared with the existing formulas in current literatures and codes.

Disk for a blisk rotary stage of a gas turbine engine

Abstract: A disk for a BLISK rotary stage of a gas turbine engine includes a stub on the tapered circumferential surface of a turbine disk, the stub defining a weld joint surface on the radially outermost face of the stub. The weld joint surface follows the annulus curvature in axial and circumferential directions while remaining flat in a third direction. A blade is applied radially to the stub and linear friction welding of the blade to the stub is effected by oscillating the blade in said third direction while applying a welding force inwardly along the blade.

Single switch reconfigurable bandpass filter with variable bandwidth using a dual-mode triangular patch resonator

Abstract: A reconfigurable bandpass filter is demonstrated using a dual-mode microstrip triangular patch resonator. The proposed circuit uses a single switch to control its fractional bandwidth while keeping a fixed center frequency of 10 GHz. The switching mechanism is accomplished by a p-i-n diode that connects and isolates a tuning stub from the rest of the circuit. The on and off state of the diode effectively controls the resonance frequencies of the two poles, produced by the dual-mode behavior of the resonator. The filter achieves a measured 1.9:1 tunable passband ratio. The circuit presented here represents the first single switch bandwidth reconfigurable filter that requires no size compensation to maintain a fixed center frequency.

Opening device for can

Abstract: The present invention relates to an opening device for a can, which is constructed such that the contents of the can flow out and exterior air is simultaneously introduced into the can. The opening device of the present invention comprises first and second opening portions 122 and 124 through which the contents flow out and the exterior air is introduced into the can upon opening thereof, respectively, and which are disposed to be opposite to each other at both sides of the top surface 110 of the can and defined by incision lines 122a and 124a so that a part of each of the opening portions is attached to the top surface; and a tab 140 mounted on the top surface of the can by means of a first rivet stub Ra installed outside of the first opening portion and a second rivet stub Rb installed within the second opening portion. The second opening portion is opened while being lifted together with the second rivet stub Rb, the first opening portion is opened while being pressed by a pressing portion 144 around the first rivet stub, and the second rivet stub is formed to be closer to a grip 172 of the tab 170 than the first rivet stub.