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An Overview of Smart Antenna Technology for Wireless Communication
Published in Prashant Ranjan, Ram Shringar Rao, Krishna Kumar, Pankaj Sharma, Wireless Communication, 2023
Prashant Ranjan, Ram Shringar Rao, Krishna Kumar, Pankaj Sharma
The basic architecture of the switched beam system is shown in Figure 7.3. A Switching Matrix is combined with an array of N antennas, which adds the signals at the RF stage and generates N different radiating beams as an output. A Butler matrix is used as a Switching Matrix. A Butler matrix is a beamforming network used to feed antenna elements. Butler matrix controls the direction of radiated beams, of radio transmission. It consists of a n×n matrix of hybrid couplers and fixed-value phase shifters where n is the power of 2. Matrix has N input ports from which power is applied, and N output ports connected with N antenna elements. The direction of the beam is controlled by power switching to the desired input port. This type of smart antenna system uses a separate smart receiver to observe the signal strength at every port of the antenna for all subscribers, and selects the antenna port for a specified user with the highest received signal strength. Then another switch generates a line from the output port of the antenna to the desired radio frequency channel.
B
Published in Philip A. Laplante, Comprehensive Dictionary of Electrical Engineering, 2018
buzz stick device should keep its tenure as short as possible to avoid interference with higher priority devices. See also bus priority. bus transaction the complete sequence of actions in gaining control of a bus, performing some action, and finally releasing the bus. See also bus cycle. bus watching See bus snooping. bushing transformer a potential transformer which is installed in a transformer bushing so as to take advantage of the insulating qualities of that bushing. busway a specialized raceway which holds uninsulated bus bars in a building. busy tone multiple access (BTMA) synonym for idle tone multiple access. See also idle tone multiple access. busy waiting a processor state in which it is reading a lock and finding it busy, so it repeats the read until the lock is available, without attempting to divert to another task. The name derives from the fact that the program is kept busy with this waiting and is not accomplishing anything else while it waits. The entire "busy loop" may be only 2 or 3 instructions. "Busy waiting" is generally deplored because of the waste of processing facilities. Butler matrix a feed system (also called beamforming system), that can excite an antenna array so that it produces several beams, all offset from each other by a finite angle. The system makes use of a number of input ports connected through a combination of hybrid junctions and fixed phase shifters. Butterworth alignment a common filter alignment characterized by a maximally flat, monotonic frequency response. Butterworth filter an IIR (infinite impulse response) lowpass filter with a squared magnitude of the form: |H ()|2 = 11 + ( j jc 2N ).
Low loss waveguide-based Butler matrix with iris coupling control method for millimeterwave applications
Published in Waves in Random and Complex Media, 2023
Muataz W. Almeshehe, Noor Asniza Murad, Mohamad Kamal A. Rahim, Osman Ayop, Farid Zubir, Mohamad Zoinol A. Abd. Aziz, Mohamed N. Osman, H. A. Majid
Generally, the configuration of 4 × 4 butler matrix consists of 3-dB couplers, 0-dB crossovers, and 45° phase shifters as illustrated in Figure 1. When various input ports are excited, four uniform amplitudes with different phases will be produced at outputs. The standard output phase differences with respect to the inputs are summarized in Table 1. Therefore, an antenna array fed by Butler matrix network is able to steer four beams in different directions (as in Table 1).