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Search Results for ultra-wideband

Article
Antenna Design for Ultra-Wideband System Using a Fractal H-Shaped Structure for Enhanced Filtering and Narrowband Operation

Noor K. Mohsin, Dhirgham K. Naji

Pages: 515-523

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Abstract

In this work, for ultra-wideband (UWB) applications, a passive filter antenna with edge chamfering is investigated in this paper. The performance of an optimized UWB antenna design that achieves an advanced fractional impedance bandwidth of 102% is confirmed by simulation and experimentation. The performance of the antenna is improved by integrating a lowpass filter (LPF) into the fed line, which suppresses high-frequency radiation with a central frequency of 3.5 GHz (WiMAX), the UWB antenna has been transformed into a narrowband antenna, offering a 43.7% fractional bandwidth that spans the frequency range from 2.7 GHz to 3.9 GHz. A stepped impedance transmission line and an extended fractal H-shaped structure integrated in the microstrip feedline make up the filtering network. Using CST Microwave Studio (CST MWS), key performance parameters such as the radiation patterns, efficiency, gain, and reflection coefficient (S11) were examined. In its prototype, the antenna reduces its size by 5% and is made on a FR4 substrate with a permittivity coefficient of 4.3 and a loss tangent of 0.02. A maximum gain of 1.7 dBi and a peak efficiency of 78% at the center frequency were verified experimentally. The center frequency was verified experimentally. The tiny antenna, which measures 0.30λ₀ × 0.37λ₀ × 0.008λ₀, performs well and is appropriate for UWB applications. The design makes a significant addition to the realm of UWB technology by incorporating elements that improve its ability to adapt.

Article
Performance Investigation of DP-16QAM Ultra-wideband- Wavelength-Division Multiplexing Communication System: Optimum Power Consideration

Arwa Moosa, Raad Sami Fyath

Pages: 37-44

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Abstract

Recently, there is increasing interest in using the 18 THz bandwidth offered by S+C+L band to increase the transmission capacity of fiber communication systems. This leads to the generation of ultra-wideband (UWB) wavelength-division multiplexing (WDM) optical communication systems. In these advanced systems, stimulated Raman scattering (SRS) causes a power transfer from high-frequency channels to low-frequency channels. This effect leads to an increase in the nonlinear interference (NLI) between the UWB-WDM channels. Power optimization techniques are required to balance transfer power between band channels, thus increasing the maximum transmission reach (MTR) along with increasing system capacity. In this paper, the transmission performance of S+C+L band system operating with dual-polarization 16-QAM signaling is investigated using enhanced Gaussian noise model. The transmitter and receiver for each DP channel use a -polarized laser and incorporate two identical configurations, one for x- and the other for y-state of polarization (SOP). The results are presented for two values of symbol rate, 40 and 80 GBaud, where the system carries 360 (=160+80+120) and 180 (=80+40+60) channels, respectively. The results revel that the MTR of both cases is equal to 12 100 km-spans when the channel lunch power equals to -4 and -2 dBm, respectively. This work also shows the effect of NLI components as a function of the number of spans, channel spacing, and channel launch power. The results show that the cross-phase modulation component of the NLI has high accumulated value with transmission distance, while the self-phase modulation component is almost constant.

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