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Author

Li Li

Bio: Li Li is an academic researcher from University of Electronic Science and Technology of China. The author has contributed to research in topics: Monopole antenna & Signal edge. The author has an hindex of 4, co-authored 6 publications receiving 147 citations.

Papers
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Journal ArticleDOI
TL;DR: In this paper, a dual-band-notched ultra wideband (UWB) antenna is presented, which consists of a trapezoidal ground plane with a rectangle slot, a Y-shaped monopole used as the radiator, together with a modified complementary co-directional splitering resonator (SRR) etched on the radiation patch, leading to the desired dual notched bands for lower and upper bands of the WLAN.
Abstract: To prevent interference problems due to existing nearby communication systems within an ultra-wideband (UWB) operating frequency, a compact dual-band-notched UWB antenna is presented. This antenna consists of a trapezoidal ground plane with a rectangle slot, a Y-shaped monopole used as the radiator, together with a modified complementary co-directional splitering resonator (SRR) etched on the radiation patch, which leads to the desired dual notched bands for lower and upper bands of the WLAN. Experimental results show that the designed antenna, with compact size of 24×25×mm, has a wide bandwidth covering 3.05-14.2 GHz, realising dual notched bands of 5.14-5.36 and 5.74-6.07 GHz.

89 citations

Journal ArticleDOI
TL;DR: In this article, a novel compact ultra wideband (UWB) antenna with dual-band notched characteristics is presented, by adding a pair of Y-shaped strips to the annular ring, and etching an inverted Ω-shaped slot on the patch.
Abstract: A novel compact ultra-wideband (UWB) antenna with dual-band notched characteristics is presented. By adding a pair of Y-shaped strips to the annular ring, and etching an inverted Ω-shaped slot on the patch, dual-band notched function in the WiMAX/WLAN is achieved. Experimental results show that the designed antenna, with compact size of 24 × 28 mm 2 , has a measured impedance bandwidth of 2.91-11.4-GHz for VSWR<;2, except two frequency notched bands of 3.3-3.73 and 5.2-5.98-GHz. Moreover, this antenna exhibits very good omnidirectional radiation patterns in the H-plane.

34 citations

Journal ArticleDOI
Abstract: A novel compact ultra-wideband (UWB) monopole antenna with four band-notched characteristics is presented. Three crescent-shaped resonators coupled to the radiating patch are used to create three notched bands at 4.94–5.52 GHz, 5.72–6.02 GHz for WLAN and 7.25–7.76 GHz for downlink of X-band satellite communication systems. In addition, an inverted U-slot is cut in the ground plane to generate the fourth notched band at 8.01–8.55 GHz for the ITU band. The proposed antenna has been successfully fabricated and measured, showing broadband matched impedance (3.05–14 GHz, VSWR<2), stable gain and good omnidirectional radiation patterns. Moreover, the designed antenna has a compact size of 25×28 mm.

26 citations

Journal ArticleDOI
TL;DR: Experimental results show that the proposed approach can effectively reduce the error introduced by the quantisation error of ±1, improve measurement accuracy by about 2 to 3 bit, reduce measurement uncertainty by more than 20% and diminish the processing time to 200 ns compared with the traditional methods under the same conditions.
Abstract: A burst carrier frequency measurement scheme combined with a timestamping counting method based on a field programmable gate array (FPGA) is proposed. With the multiplication and phase shift of count clock, multiple parallel counters are continuously counted, and the times of the rising edge of the unknown frequency fx are counted simultaneously. To obtain the frequency of fx , linear regression by use of least-squares line fitting is used. Experimental results show that the proposed approach can effectively reduce the error introduced by the quantisation error of ±1, improve measurement accuracy by about 2 to 3 bit, reduce measurement uncertainty by more than 20% and diminish the processing time to 200 ns compared with the traditional methods under the same conditions.

6 citations

Journal ArticleDOI
TL;DR: Experimental results show that the proposed approach can effectively reduce the error introduced by the quantization error of ±1, improve measurement accuracy by about 2 to 3 digits, reduce measurement uncertainty by more than 20%, and diminish the processing time to 200 ns compared to traditional methods under the same measurement conditions.
Abstract: This paper proposes an instantaneous burst carrier frequency measurement scheme combined with timestamping counting method based on field programmable gated array. With the multiplication and phase shift of counting clock, multiple parallel counters run continuously, and the times of rising edge of measured frequency fx are counted simultaneously. The frequency of fx is calculated using the least squares line fitting method of regression analysis from the count values of fx and timestamping clock. Experiment results show that the proposed approach can effectively reduce the error introduced by the quantization error of ±1, improve measurement accuracy by about 2 to 3 digits, reduce measurement uncertainty by more than 20%, and diminish the processing time to 200 ns compared to traditional methods under the same measurement conditions.

Cited by
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Journal ArticleDOI
TL;DR: In this article, a compact printed ultrawideband (UWB) slot antenna for MIMO/diversity applications is presented, which consists of two modified coplanar waveguides (CPWs) feeding staircase-shaped radiating elements for orthogonal radiation patterns.
Abstract: A novel compact printed ultrawideband (UWB) slot antenna for MIMO/diversity applications is presented in this letter. The antenna consists of two modified coplanar waveguides (CPWs) feeding staircase-shaped radiating elements for orthogonal radiation patterns, where a rectangle stub is placed at 45° between the CPW to ensure high isolations. By etching two split-ring resonator (SRR) slots on the radiators respectively, the band-notched property is achieved. Results show that this antenna meets a 10-dB impedance bandwidth and 15 dB isolation from 2.5 to 12 GHz, with a notched band at 5.5 GHz. The measurements of the radiation patterns and envelope correlation coefficient (ECC) denote that the antenna is suitable for multiple-input-multiple-output (MIMO)/diversity systems. Furthermore, it has a compact size of 48 × 48 mm2, which has been significantly reduced, and it is a good candidate for portable devices.

261 citations

Journal ArticleDOI
TL;DR: In this paper, the design of a compact split ring resonator (SRR) loaded coplanar waveguide (CPW) fed ultrawideband circular monopole antenna having frequency notch characteristics is presented.
Abstract: This paper presents the design of a compact split ring resonator (SRR) loaded coplanar waveguide (CPW) fed ultrawideband circular monopole antenna having frequency notch characteristics. The electromagnetic coupling of the SRR with the CPW yields the frequency notch. Fabricated prototypes were measured and compared with simulations and good agreement was obtained. The impedance and radiation plots confirm the suppression of the desired notch frequency. A theoretical formulation to calculate the notch frequency is also proposed and validated.

192 citations

Journal ArticleDOI
TL;DR: In this article, a compact octagonal shaped fractal ultrawideband multiple-input-multiple-output (MIMO) antenna is presented, and its characteristics are investigated in order to achieve the desired miniaturization and wideband phenomena.
Abstract: In this letter, a compact octagonal shaped fractal ultrawideband multiple-input–multiple-output antenna is presented, and its characteristics are investigated In order to achieve the desired miniaturization and wideband phenomena, self-similar and space filling properties of Koch fractal geometry are used in the antenna design These fractal monopoles are placed orthogonal to each other for good isolation Moreover, grounded stubs are used in the geometry to provide further improvement in the isolation The band rejection phenomenon in wireless local area network band is achieved by etching a C-shaped slot from the monopole of the antenna The proposed antenna has compact dimensions of $45~\hbox{mm} \times 45~\hbox{mm}$ and exhibits quasi-omnidirectional radiation pattern In addition, it shows an impedance bandwidth ( ${{\rm S}_{11}}\! ) from 2 to 106 GHz with isolation better than 17 dB over the entire ultra-wideband range Diversity performance is also evaluated in terms of envelope correlation coefficient and capacity loss The measured results show good agreement with the simulated ones

188 citations

Journal ArticleDOI
TL;DR: In this paper, a dual-split-ring-resonator (SRR)-loaded coplanar waveguide (CPW)-fed ultrawideband circular monopole antenna exhibiting dual frequency notch and wideband notch characteristics is presented.
Abstract: This letter presents the design of a compact dual-split-ring-resonator (SRR)-loaded coplanar waveguide (CPW)- fed ultrawideband circular monopole antenna exhibiting dual frequency notch and wideband notch characteristics. The SRR pairs are inductively coupled to the radiator and loaded on the back side of the CPW line. Fabricated prototypes were measured and compared to simulations, and good agreement was obtained.

124 citations

Journal ArticleDOI
TL;DR: In this article, a band-notched ultra wideband (UWB) slot antenna with bandnotched characteristics is proposed, where a stepped slot is adopted as a radiator to realize UWB impedance matching and reduce the antenna size.
Abstract: A compact ultra-wideband (UWB) slot antenna with band-notched characteristics is proposed. A stepped slot is adopted as a radiator to realize UWB impedance matching and reduce the antenna size. By slitting an open-ended quarter-wavelength split slot on the back of the feed and a short-ended half-wavelength split-ring slot near the stepped slot, a second-order notched band of 5.15-5.85 GHz is achieved. Compared with the traditional band-notched antenna, the selectivity of the notched band is greatly improved and size of the antenna is reduced at the same time. The volume of the antenna is only 22 mm×8.5 mm×0.8 mm. Besides, the bandwidth can be easily controlled by adjusting the lengths of the two slots respectively. Good agreement is achieved between simulated and measured results, which show that the proposed antenna has nice impedance matching and radiation pattern characteristics.

91 citations