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Optical generation of ultra-wideband signals with a reconfigurable spectral notch-band

100%

Xiang P. , Chen Y. , Chen D. , Zhao J.

Optica Applicata

2014

tom Vol. 44, nr 3

411--419

A novel method for optical generation of ultra-wideband signals with a reconfigurable spectral notch-band is proposed. In the proposed system, ultra-wideband signals are generated in the optical domain and an optical tunable delay line is deployed to introduce a notch-band to the spectral profile of the generated ultra-wideband signals, which can effectively avoid the signal interference between ultra-wideband signals and pre-planned narrowband wireless signals used in wireless local area networks (WLAN). A theoretical model describing the proposed system is derived; the optical generation and fiber transmission of ultra-wideband signals with a reconfigurable notch-band are demonstrated via computer simulations.

Polarity-reversed ultra-wideband monocycle pulse generation with dual-channel multicasting in a photonic crystal fiber

88%

Gong J. , Hui Z.

Optica Applicata

2015

tom Vol. 45, nr 1

25--39

This paper proposes and demonstrates a novel scheme of a two-channel-output ultra-wideband monocycle pulse generator consisting of a 100 m dispersion-flattened highly nonlinear photonic crystal fiber and two optical bandpass filters. Based on the cross-phase modulation effect in a dispersion-flattened highly nonlinear photonic crystal fiber, two polarity-reversed ultra-wideband monocycle pulses simultaneously output from two different channels are successfully achieved by appropriately locating the probe wavelength at the left linear slope and the right linear slope of the two optical bandpass filters transmission spectra, respectively. The full width at half-maximum and a fractional bandwidth of 24 ps and 260% for a positive pulse, 24 ps and 251% for a negative pulse are obtained. Moreover, the influences of input signal powers, the polarization misalignment between the data light and the continuous wave probe light, and probe wavelength variation on the double output ultra-wideband signals quality are also investigated. The results show that the system has some tolerance to both the input signal power fluctuation and the slight polarization mismatch and even can efficiently operate with a widely tunable wavelength range. This makes it very attractive for engineering applications in future multiuser ultra-wideband-over-fiber communication systems.

Integrated filtering antenna with high selectivity band rejection for UWB applications

88%

Alhegazi A. , Zakaria Z. , Shairi N. , Salleh A. , Ahmed S.

Przegląd Elektrotechniczny

2016

tom R. 92, nr 9

224--228

In this paper, a new design composed of an UWB monopole antenna integrated with bandstop filter (BSF) has been proposed. The bandstop filter is constructed by using a defected microstrip structure (DMS). The proposed design covers frequency bandwidth from 3 GHz to 14 GHz (129.5%), with single band rejection from 5.1 GHz to 5.8 GHz (12.8%). The new integration of filter and antenna shows a high level of rejection, wide impedance bandwidth, realized peak gain of 5.23 dB and stable omnidirectional azimuth pattern. Therefore, the proposed design is suitable to be used in reducing the possible interference problem for the UWB applications.

W artykule opisano projekt anteny UWB ze zintegrowanym filtrem. Filtr został wykonany z wykorzystaniem struktury mikropaska . Antena umożliwia wykrywanie sygnałów w paśmie 3 – 14 GHz z możliwością usuwania pasma 5.1 – 5.8 GHz. Umożliwia to rozwiazywanie problemu interferencji fal.

Poprawa warunków międzysystemowej kompatybilności elektromagnetycznej radia impulsowego

75%

Sadowski J. , Katulski R. J.

Zeszyty Naukowe Wydziału ETI Politechniki Gdańskiej. Technologie Informacyjne

2008

tom T. 15

31-36

Referat zawiera opis jednej z możliwych technik modyfikacji widma sygnału ultraszerokopasmowego radia impulsowego na przykładzie standardu IEEE 802.15.4a, opartą o zmianę struktury sekwencji generowanych impulsów o bardzo krótkim czasie trwania. Technika ta może zmniejszyć ryzyko wzajemnych zakłóceń pomiędzy nowymi urządzeniami ultraszerokopasmowymi a istniejącymi urządzeniami radiokomunikacji wąskopasmowej.

This article presents one of possible techniques of IEEE 802.15.4a ultra-wideband signal spectrum control, based on changes in sequences of transmitted pulses with very short duration time. This technique can reduce probability of mutual interferences between new ultra-wideband and existing narrowband devices, which may be helpful in further studies on allowing UWB transmission in wider range of spectrum in the European Union.