L band

About: L band is a research topic. Over the lifetime, 674 publications have been published within this topic receiving 4570 citations.

Wideband Channel Characterization for Low-Elevation Satellites in L-Band

Abstract: The results of a wideband measurement campaign carried out at L-band in order to characterize the receiver end of the radio link between satellites with elevations lower than 5 $^{\circ}$ and mobile receivers are summarized in this paper. A swept time-delay cross-correlation (STDCC) channel sounder with 1.675-GHz carrier frequency and 12.5-ns delay resolution was used to obtain complex low-pass impulse responses of the propagation channel in urban, suburban, rural, lightly wooded, and heavily wooded environments. Delay spreads and coherence bandwidths have been obtained and studied according to three different propagation conditions. Results show how shadowing and blockage together with the propagation environment impact on the delay spread and the coherence bandwidth.

Wideband low noise amplifier using a novel equalization

Abstract: This paper prevents a wideband low noise amplifier worked in L band and S band using a new equalization structure. Usually, in order to design a wideband amplifier, we should use an equalization to compensate for inconsistencies in active component's gain response. Microstrip equalizer is always composed of microstrip transmission line coupled with microstrip resonators and resistance. It is known that the limit of a traditional microstrip equalization corresponding is the one quarter length transmission line. So it usually can work only in an octave band. In the paper, we prevent a novel equalization that can work a wide band which the high frequency of the work band is more than three time the low frequency of the work band. And the equalization is also smaller than traditional equalization. We finally use design a equalization which works from 1 GHz to 3 GHz. Then we designed a wideband low noise amplifier using the equalization. This LNA works from 1 GHz to 2.6 GHz. It covers over the GPS band to WiFi band. This amplifier is cascaded by three pHEMT ATF54143. The gain of the amplifier is more than 35 dB. And it simulation noise figure is below 1.1 dB all over the band. The substrate we use is FR4 with the thickness of 0.8 mm.

Low cost phase shifters for L-band phased array antennas

Abstract: This paper discusses the methods of designing good quality PIN diode phase shifters for operation at L-band using low cost PIN diodes. This is demonstrated in the design example of a 4-bit phase shifter for possible use in an L-band vehicle mounted phased array antenna for mobile satellite communications. It is shown that the performance of the phase shifters can be of good quality over a 7% bandwidth (between 1.54 GHz and 1.66 GHz) as is required for the Mobilesat system in Australia. This quality performance is achieved by including extra compensation circuits in the biasing networks of the PIN diodes. By using these extra compensation networks, the parasitic elements are tuned out producing almost ideal on-off switches and therefore good quality phase shifters over the required frequency band.

Radio wave propagation characteristics measurement and modeling over the sea

Abstract: Radio wave propagation test is introduced in this paper. It was held in the sea area near Qingdao city, and involved different band including L band, S band, C band and X band. Using the path loss model given in the International Telecommunication Union (ITU) recommendation propagation 1411, we derived the characteristic parameters such as path loss exponent and shadow fading for different frequencies. The statistic propagation model can be used for providing a reference for ship information communication.