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• Interview

  • Author(s): Paul Berger
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  • p. 436 (1)
    Professor Paul Berger from Ohio State University in the US talks about the research behind his group's Letter: ‘Towards in vivo biosensors for low-cost protein sensing’ on page 450.
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• In Brief

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  • p. 436 (1)
    
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• A good fit

  • Author(s): D. Davies
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  • p. 437 (1)
    A US-based team have expanded their model of III-V materials interfaces to include series resistance and dielectric leakage behaviour.
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• Nod off – switch off

  • Author(s): J. Baldwin
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  • p. 438 (1)
    Researchers in China have presented a device for identifying when a patient is asleep and accordingly to adjust deep brain stimulation (DBS) in Parkinson's disease sufferers. The device is worn on the wrist and can communicate with the implanted stimulating system to control its activity.
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• Bandwidth enhancement of ground antenna using resonant feeding circuit

  • Author(s): R. Zhang; Y. Liu; H.H. Kim; H. Kim
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  • p. 441 –442 (2)
    A loop-type ground antenna with wide-band operation is proposed for USB dongle applications. The solution for improving the bandwidth is based on a resonant feeding circuit that includes both an inductor and a capacitor. By choosing an appropriate ratio of the inductance to the capacitance, the impedance bandwidth (VSWR < 2) is 21.8% at 2.2 GHz, sufficient bandwidth to cover both the WCDMA and WiMax frequency bands.
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• Compact shorted inverted-L antenna with circular polarisation for RFID handheld reader

  • Author(s): Y.F. Lin; H.M. Chen; C.H. Chen; C.H. Lee
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  • p. 442 –444 (3)
    Two shorted inverted-L radiating elements are located on the orthogonal corner of the square substrate and connected to each output port of a Wilkinson power divider. A shorted inverted-T strip is placed on the other corner of the square for a perturbing resonator to generate circularly-polarised (CP) radiation in the UHF band. Proper adjusting of the horizontal and vertical lengths of the inverted-T strip will differentiate two orthogonal linearly modes with 90° phase difference for a good CP radiation. Simulated and measured results indicate that the proposed structure can achieve circular-degree polarisation operation. A measured impedance bandwidth (VSWR ≤ 2) of about 16.4% (810–960 MHz) and a 3 dB axial-ratio (AR) bandwidth of about 4.4% (890–930 MHz) at 915 MHz were obtained.
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• Dual-band circularly-polarised Spidron fractal microstrip patch antenna for Ku-band satellite communication applications

  • Author(s): T. Nguyen Thi; K.C. Hwang; H.B. Kim
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  • p. 444 –445 (2)
    A dual-band circularly-polarised antenna implemented on a single substrate is proposed for Ku-band satellite communication. A microstrip-fed Spidron fractal patch is utilised to achieve dual-band resonance and circular polarisation. The proposed antenna, with dimensions of 50 × 50 × 1.52 mm³, has also been fabricated and tested. The measured −10 dB reflection bandwidths are 8.7% (11.44–12.48 GHz) and 6.6% (13.47–14.39 GHz), exhibiting a small resonant frequency ratio of 1.15. The 3 dB axial ratio bandwidths for the lower band and the upper band are 2.96 and 1.68%, respectively.
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• Electronically scanned Rotman lens antenna with liquid crystal phase shifters

  • Author(s): S. Christie; R. Cahill; N. Mitchell; Y. Munro; A. Manabe
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  • p. 445 –447 (3)
    The performance of a Rotman lens, which forms fixed beams at 0°, ±15° and ±30°, is augmented using liquid crystal phase shifters to simultaneously steer each beam by up to ±7.5°. Measured results are used to demonstrate that the true time delay property of the antenna and voltage controlled phase shifters can be exploited to provide continuously scanned beams with full coverage over an angular range of ±37.5°, and with operation over the band 6–10 GHz.
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• Ground radiation method using slot with coupling capacitors

  • Author(s): Y. Liu; J. Lee; H.H. Kim; H. Kim
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  • p. 447 –448 (2)
    An innovative antenna radiation method for exciting a dipole-type radiation mode in the ground plane of mobile devices is proposed. This method is based on a capacitively loaded slot placed at the centre of the ground plane. The ground plane is 50 × 15 mm in length and width, respectively, which is the size typically used in USB dongles and headsets. The −10 dB impedance bandwidth is 12.9% at 2.4 GHz, fully covering the WiMax, Wi-Fi and Bluetooth frequency bands.
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• Fuzzy extreme learning machine for classification

  • Author(s): W.B. Zhang; H.B. Ji
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  • p. 448 –450 (3)
    Compared to traditional classifiers, such as SVM, the extreme learning machine (ELM) achieves similar performance for classification and runs at a much faster learning speed. However, in many real applications, the different input points may not be exactly assigned to one of the classes, such as the imbalance problems and the weighted classification problems. The traditional ELM lacks the ability to solve those problems. Proposed is a fuzzy ELM, which introduces a fuzzy membership to the traditional ELM method. Then, the inputs with different fuzzy matrix can make different contributions to the learning of the output weights. For the weighted classification problems, FELM can provide a more logical result than that of ELM.
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