Stub (electronics)

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

Compact uwb filter based on surface-coupled structure with dual notched bands

Abstract: A novel compact ultra-wideband (UWB) band-pass fllter (BPF) based on surface-coupled structure is proposed. The surface- coupled structures and Y-shaped shorted stub resonator are adopted as quasi-lumped circuit elements to achieve UWB pass-band. To avoid the interference of the wireless local area network (WLAN) at 5.25 and 5.775GHz, two difierent quarter-wavelength lines are arranged on the ground of UWB BPF to generate dual narrow stop bands. Being developed from the quasi-lumped elements, the proposed UWB BPFs have very compact size. The fabricated UWB BPFs have the advantages of low insertion loss, good selectivity and ∞at group delay. Good agreement between equivalent circuit modeled, simulated and measured responses of these fllters is demonstrated.

A Single-Layer Ultrawideband Microstrip Antenna

Abstract: A single-layer microstrip antenna for ultrawideband (UWB) applications, in which an array of rectangular microstrip patches was arranged in the log-periodic way and proximity-coupled to the microstrip feeding line, is presented. In order to reduce the number of microstrip patches in the UWB log-periodic arrays, a large scale factor k = 1.1 was firstly reported and proved to be highly effective. Furthermore, instead of using an absorbing terminal loading, a novel loss-free compensating stub was proposed. Detailed parameters study was also presented for better understanding of the proposed antennas. The impedance bandwidth (measured VSWR < 2.5) of an example antenna with only 11 elements is from 2.26-6.85 GHz with a ratio of about 3.03:1. Both numerical and experimental results show that the proposed antenna has stable directional radiation patterns, very low-profile and low fabrication cost, which are suitable for various broadband applications.

Compressive performances of the concrete filled circular cfrp-steel tube (c-cfrp-cfst)

Abstract: This paper presents the results of axial compressive tests of the concrete filled circular CFRP-steel tubular (C-CFRP-CFST) stub columns. The test results showed that the CFRP jackets enhanced the load bearing capacity of the stub columns effectively. Enhancement of the columns' stiffness due to the CFRP jackets was also observed. Also, the steel tube and the CFRP tube work concurrently before failure. A constitutive relationship suitable for concrete confined by circular CFRP-steel composite tube was proposed, and a finite element model was established by using ABAQUS for analyzing load-deformation relationship of the composite stub columns and it shows that the results predicted check well with that of the test and were on the safe side. Analysis based on ABAQUS indicates that, outer tube of the C-CFRP-CFST stub columns can provide confinement force for concrete core even during initial loading period. Additionally, the initial stress in the steel tube can postpone the mutual reaction between the steel tube and the concrete, while it has a little influence on the peak value of the confinement force; adhesive strength has little effect on compressive performances of the stub columns. Finally, the index and parametric expression of load bearing capacity of the C-CFRP-CFST stub columns were proposed, and the proposed equations can be used to calculate the load bearing capacity reasonably.

Differential Dual-Band Bandpass Filter With Tunable Lower Band Using Embedded DGS Unit for Common-Mode Suppression

Abstract: This paper presents a varactor- and stub-loaded dumbbell-shaped resonator (VSDSR) for application in differential dual-band bandpass filter, which possesses a tunable lower passband and a fixed upper passband. Under differential-mode (DM) bisection, the VSDSR behaves as a ring resonator with four resonant modes, which can be categorized into two independent groups for constructing two passbands. At the same time, the common-mode (CM) equivalent circuit of the VSDSR generates multiple CM resonant frequencies and some of them inevitably overlap with the DM ones. Accordingly, the traditional CM suppression methods such as adding shunt stub or lumped element are disabled. To suppress the CM signals in both DM passbands, the defected ground structure (DGS) units are embedded underneath the adjacent edges of the two rings directly to form a CM suppression filter without increasing the circuit size. Meanwhile, they have almost no effect on the DM responses. Benefitting from the bandstop and slow-wave effects of the employed DGS units, the CM noises in both DM bands can be rejected effectively. In particular, the level of the CM suppression in the DM lower passband can be improved by adjusting the location of the DGS units. Furthermore, the proposed CM suppression scheme is adaptive in the tunable lower DM passband.