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Stub (electronics)

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


Papers
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01 Jan 2009
TL;DR: In this article, a rectangular slot with an appropriate location and a proper size is introduced into the ground plane of the system printed circuit board to improve the bandwidth of PIFA antennas in both the low (GSM850/GSM900) and high (DCS1800/PCS1900) bands.
Abstract: In order to overcome the shortcoming of narrow bandwidth for conventional planar inverted-F antenna (PIFA), a novel bandwidth enhancement approach for internal multi-band handset antennas is proposed in this paper. In particular, a rectangular slot with an appropriate location and a proper size is introduced into the ground plane of the system printed circuit board to improve the bandwidths of handset antennas in both the low (GSM850/GSM900) and high (DCS1800/PCS1900) bands. The in∞uences of the slot with difierent locations and sizes on antenna bandwidth are investigated. A prototype that can cover the frequency bands of GSM850, GSM900, DCS1800 and PCS1900 simultaneously was fabricated and measured. Good agreement between the measurement and simulation results is achieved. Nowadays, modern wireless communication technologies are in the process of rapid development. Multi-system applications have been used explosively. Owing to this, it bas been a necessity to design antennas with the characteristics of multiband and wideband for mobile terminals. At present, planar inverted-F antenna (PIFA) is being adopted extensively as handset antennas because of its advantages of compact structure, low proflle, easy fabrication, low manufacturing cost and easy integration with portable devices. However, a major disadvantage of the PIFA antenna is its narrow impedance bandwidth. Hence, it is desirable to flnd methods that can enhance the bandwidths of the PIFA antennas. The bandwidth of the PIFA antenna described in (1) is broadened by using a tapered-type radiating patch. Multi-layer patches and a folded stub are introduced into the internal PIFA to improve its bandwidth (2). The bandwidth enhancement approaches mentioned above both focus on making modiflcations on the radiating elements of PIFA antennas. There are also other bandwidth improvement methods concentrating on making modiflcations on the system ground plane of mobile terminals. For example, a T-shaped ground plane is reported to broaden the bandwidth of the PIFA antenna (3). A slotted ground plane for handset devices is described to lower the proflle and improve the bandwidth of PIFA antennas (4,5). The bandwidth of the PIFA antenna designed in (6) is enhanced by using quarter-wavelength wavetraps. In this paper, a novel technique that is used to broaden the impedance bandwidth of traditional multi-band PIFA antennas is presented. In particular, a rectangular slot is introduced into the ground plane of mobile chassis. By varying the location and size of the slot, the equivalent length of the ground plane can be adjusted to the optimal lengths of the low and high bands, which thus enhance the bandwidths of PIFA antennas for both the low and high bands. The in∞uences of difier- ent slot locations and sizes on the bandwidths of the low and high bands are studied and analyzed. Based on this study, a compact internal quad-band (GSM850/GSM900/ DCS1800/PCS1900) PIFA antenna with only a volume of 20£40£6mm 3 was constructed and measured. The measurement results agree well with the simulation ones.

23 citations

Patent
03 Feb 1976
TL;DR: In this article, a multi-purpose labor-saver wheeled tool with a frame which includes a pair of laterally spaced wheels adjustably mountable on stub axles in selected holes of respective vertical arrays of holes in paired side plates is described.
Abstract: A multi-purpose labor-saver wheeled tool having a frame which includes a pair of laterally spaced wheels adjustably mountable on stub axles in selected holes of respective vertical arrays of holes in paired side plates, a handle symmetrically extends rearwardly from a rearwardly-upwardly-sloped central plate joining the side plates; an upright front plate joins the side and central plates; the plate assembly forms a load-carrying region at the top, and all the individual plates have holes for attachment of co-acting accessory members, including both fixed-, and reel-and cable-pivotable blades for snow and ice removing, rakes, and scoops; hose-reel, squeegee, and brush embodiments are also provided.

23 citations

Patent
25 Nov 1974
TL;DR: A turbomolecular vacuum pump has a stator, a rotor having a vertical axis of rotation and disposed in the stator; a drive motor for rotating the rotor; a downwardly open, axially extending chamber in the rotor, a vertically upwardly oriented, stationarily supported stub shaft projecting into the rotor chamber; and axial, as well as radial gas bearings disposed within the rotor combustion chamber for generating gas cushions between the rotor and the stub shaft as discussed by the authors.
Abstract: A turbomolecular vacuum pump has a stator, a rotor having a vertical axis of rotation and disposed in the stator; a drive motor for rotating the rotor; a downwardly open, axially extending chamber in the rotor; a vertically upwardly oriented, stationarily supported stub shaft projecting into the rotor chamber; and axial, as well as radial gas bearings disposed within the rotor chamber for generating gas cushions between the rotor and the stub shaft.

23 citations

Journal ArticleDOI
TL;DR: In this paper, a lumped equivalent circuit model for both series and double-shunt (butterfly) connected radial stubs has been developed, which includes conductor and dielectric losses but also radiation ones, which play an important role in microstrip circuit elements.
Abstract: A lumped equivalent circuit model for both series and double-shunt (butterfly) connected radial stub has been developed. The model-simple and effective-not only includes conductor and dielectric losses but also radiation ones, which play an important role in microstrip circuit elements. Experiments widely demonstrate its suitability for implementation in available CAD (computer-aided design) programs. Furthermore, a synthesis procedure for using radial stubs in circuit design is described. An application of the proposed design procedure and simulation tools in the development of very broadband nongrounded termination is also presented. >

23 citations

Journal IssueDOI
TL;DR: In this paper, a reconfigurable bandstop filter operating at 8, 10, 13, and 15 GHz that utilizes RF MEMS switches has been developed on high-resisitivity silicon substrate.
Abstract: A monolithic, low-power reconfigurable bandstop filter operating at 8, 10, 13, and 15 GHz that utilizes RF MEMS switches has been developed on high-resisitivity silicon substrate. The filter is based on microstrip transmission lines with radial stubs that provide different reactance at different resonant frequencies. Selection of the desired stub reactance is achieved with cantilever capacitive RF MEMS switches that are electrostatically actuated. The tuning range of the fabricated filter is 7 GHz (8–15 GHz), which is about 60p of the mid-band frequency. The rejection at the notch of the filter and the -10-dB bandwidth range from -20 dB to -27 dB and 5p to 9.7p, respectively, at the different resonant frequencies The pass-band insertion loss was found to be around 0.5 dB. © 2004 Wiley Periodicals, Inc. Int J RF and Microwave CAE 14: 373–382, 2004.

23 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023205
2022471
2021294
2020397
2019433
2018472