Topic
Stub (electronics)
About: Stub (electronics) is a research topic. Over the lifetime, 8172 publications have been published within this topic receiving 75018 citations.
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TL;DR: With the decoupling circuit, significant improvement in antenna efficiency and data throughput demonstrates that the technique is useful for wireless terminals, where dual-band multiple-input and multiple-output antennas are used.
Abstract: This paper presents a novel technique for decoupling of two closely spaced dual-band antennas using T-stub circuits. A decoupling circuit consists of three T-stub elements, each of which provides the required phases and impedances in dual frequency bands independently. A set of general design formulas is derived for determining the electric parameters of required T-stubs. To validate the new decoupling technique, a pair of dual-band inverted-F antennas working in the 2.45- and 5.8-GHz bands and another pair of dual-band monopole antennas working in the 2.4- and 5.2-GHz bands with and without the decoupling circuit are designed, prototyped, and measured. The measured S-parameters correlate with the theoretical designed data very well. With the decoupling circuit, significant improvement in antenna efficiency and data throughput demonstrates that the technique is useful for wireless terminals, where dual-band multiple-input and multiple-output antennas are used.
61 citations
TL;DR: In this paper, an ultra-compact two-port MIMO antenna working in the frequency range of 3.1-10.6 GHz with dual band-notched characteristics is presented.
Abstract: In this paper, an ultra-compact two-port MIMO antenna working in the frequency range of 3.1–10.6 GHz with dual band-notched characteristics is presented. The MIMO antenna consists of two identical octagonal-shaped radiating elements placed adjacent to each other with a connected ground plane. The overall size of the proposed two-port UWB-MIMO antenna is 19 × 30 × 0.8 mm3. In the ground plane of antenna elements, a T-shaped stub is introduced to create band-notch at 5.5 GHz. Also, an open-ended half-guided-wavelength resonator slot is introduced along the upper edge of the octagonal radiator to obtain a broader notched-band (4.37–5.95 GHz). The second band-notch is created around 7 GHz (6.52–7.45 GHz) by etching another open-ended slot from the radiating patch. The two-notch bands reject interference due to HiperLAN, WiMAX, INSAT/Super-extended C-band, downlink of X-band satellite communication and RFID service bands. A pair of L-shaped slits are introduced in the feed line to improve impedance matching, for the frequency band available between the two notches. The proposed design is fabricated on an FR-4 substrate and minimum isolation greater than 18 dB (a major portion >22 dB) and envelope correlation coefficient (ECC) less than 0.13 are obtained. The antenna gain varies in the range of 1.2–2.91 dBi with a variation of 1.71 dBi only. A radiation efficiency, greater than 70% is achieved throughout the operating frequency band.
61 citations
TL;DR: To address the out-of-band characteristic drawback that existed in most of the previous UWB antenna, a parallel coupled band-pass filter with stepped impedance transformation and defected ground structure is incorporated in the feedline of the antenna to achieve sharp rejection at the edges of the UWB band.
Abstract: In this paper, a miniaturized fully inkjet-printed flexible multiple-input-multiple-output (MIMO) antenna for ultrawideband (UWB) application is proposed, occupying a compact size of $22\times 31\times 0125$ mm3 In the proposed antenna, two half-planar radiators are introduced to minimize the antenna size Moreover, a modified T-shaped stub is employed on the ground plane to improve the impedance performance In addition, a slot is etched on this modified T-shaped ground stub to further enhance the isolation By doing so, the proposed antenna can operate from 29 to more than 12 GHz with the mutual coupling less than −15 dB Furthermore, to address the out-of-band characteristic drawback that existed in most of the previous UWB antenna, a parallel coupled band-pass filter with stepped impedance transformation and defected ground structure is incorporated in the feedline of the antenna to achieve sharp rejection at the edges of the UWB band The measurements indicate that the proposed filter-antenna can cover from 343 to 101 GHz, with the envelope correlation coefficient below 03 and the channel capacity loss below 04 bit/s/Hz, which ensures its good MIMO performance
61 citations
TL;DR: In this paper, a linear-polarization (LP)/circular polarization switchable reconfigurable antenna using a radio frequency micro-electro-mechanical system (RF-MEMS) switch is proposed and a novel package platform is introduced.
Abstract: A linear-polarization (LP)/circular-polarization (CP) switchable reconfigurable antenna using a radio frequency micro-electro-mechanical-system (RF-MEMS) switch is proposed and a novel package platform is introduced. Since the package substrate of the novel package platform is used as a radiation aperture substrate of the antenna structure, the fabrication process can be simplified, and degradation of radiation performance can be prevented. As the radiation aperture exists on the top side of the package substrate, an aperture-coupling feed structure is employed. To implement the LP-CP-switchable antenna based on the package platform, a stub, acting as the other feed, is added to a slot ring and is connected to the RF-MEMS switch with an on/off state. The proposed antenna is simulated using the Finite-Element Method, after which it is fabricated and measured. The measured 10 dB impedance bandwidths (BWs) are 22.90% (LP state) and 28.43% (CP state). The measured 3 dB axial ratio BW is 13.07% in the CP state. The measured gains at 21 GHz are 2.63 dBi (LP state) and 3.90 dBi (CP state).
61 citations
TL;DR: In this paper, a finite element analysis (FEA) model for CFST stub columns under eccentric partial compression is developed and the predicted performances are validated through measured results and the FEA model is then used to investigate the mechanisms of such composite columns further.
Abstract: This paper investigates the behaviour of concrete filled steel tubular (CFST) stub columns subjected to eccentric partial compression. Twenty-eight specimens were tested and presented. The main parameters in test program include: (1) section type: circular, square and rectangular; (2) load eccentricity ratio (including uniaxial and biaxial loading): from 0 to 0.4; and (3) shape of the loading bearing plate (BP): circular, square, strip and rectangular. The test results indicated that, similar to the corresponding fully loaded CFST stub columns under eccentric loading, CFST stub columns under eccentric partial compression have generally reasonable bearing capacity and favorable ductility. A finite element analysis (FEA) model for CFST stub columns under eccentric partial compression is developed and the predicted performances are validated through measured results. The FEA model is then used to investigate the mechanisms of such composite columns further.
61 citations