Design of triple-mode bandpass filter using novel resonant structure

Autor: Shao-Guo Mo, Long Zhang, Zhiyuan Yu
Rok vydání: 2010
Předmět:
Zdroj: Microwave and Optical Technology Letters. 52:849-852
ISSN: 0895-2477
Popis: patterns with peaks around 615 and 645 are generated from the output ports of the first Butler Matrix when input ports are fed with signals. Alternatively, broad beam patterns are generated from the output ports of the second Butler Matrix when input ports are fed with signals. The measured radiation pattern results agree with the simulated array factor values in terms of the direction of the main beam. Generally, the measured main beams are more than 10 dB greater than the side lobes. Figure 4 illustrates the radiation pattern of the measured adaptive antenna system output from Port 2, when the HLLNAs are switched off alternately. The results are compared with the pattern when all HL-LNAs are switched on. It is clearly shown that when one of the outermost HL-LNAs, namely either HL-LNA 1 or HL-LNA4 is switched off, a null is formed at angle around 615. On the other hand, nulls are shown at angles around 635, when HL-LNA 2 or HL-LNA 3 is switched off. It is concluded from this experiment that nulls could also be formed in the broadbeam angle with the proposed active cascaded Butler Matrices system. The application of the adaptive antenna system can be illustrated as a three vehicles scenario as shown in Figure 5. Referring to the figure, two cars, Car A and Car B are moving in the same direction while car C is coming from the opposite direction. Car A and Car B are communicating between one another, and as the distance between the vehicles is small, a broad beam channel is used because the cars are moving very fast. However, interferences are received from Car C that is coming from the opposite direction. With the adaptive antenna system, the configuration of communication system using the broad beam channel between Car A and Car B doesn’t need any change to suppress the interference from Car C instead one of the HL-LNAs can be switched off to maintain the communication between the vehicles and suppress the interference. 4. CONCLUSIONS In this article, the measurement results and analysis of the active cascaded Butler Matrices system are illustrated. Broad beamhigh linearity and narrow beam-high gain signals are generated when the Butler Matrices are cascaded and integrated with the LNAs. At the output ports of the second Butler Matrix, large signals from sources close to the receiver are amplified with high linearity while signals from longer distances have the benefit of high antenna gain and narrowbeam signals from the output ports of the first Butler Matrix. This setup is potentially useful for vehicle applications when Inter Vehicle communication and Roadside to Vehicle communications are required, simultaneously.
Databáze: OpenAIRE
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