A.L. Buzov, A.D. Krasilnikov, M.A. Minkin, V.V. Yudin
This article is a short documentary of Branch NIIR – SONIIR activities in creation single- and multiport transmitting and transceiver VHF and UHF-band antennas.
Fields of practical application of single and multiport antennas are described. Field of application of singleport antenna is mainly television and VHS FM radio (transmitting antennas) they are also used to communicate mobile objects. Field of application of multiport antennas (transceiver antennas) are multichannel radiocenters to communicate to mobile objects.
Ideas to build singleport transmitter antennas that shall use proper places of specialized masts are discussed.
Structures that would allow horizontal and vertical evolution of antenna arrays are listed. Peculiarities for emitters using in-phase and quarter-phase power are described. Peculiarities of creating horizontal array structure for different polarizations (horizontal and vertical).
Problems of building power systems for transmitter antenna arrays are discussed. Ways to achieve echo suppression are described: quarter-phase powered emitters on the floor, quarter-phase of pairs of floors rotating each second 90° azimuth-wise, linear phase increase between floors tilting radiation pattern in vertical plane. The problem of signal reemission during echo suppression is addressed. It may lead to deformation of image on TV screens. To avoid that one must keep minimal geometry length of line between emitters and compensation.
Problems of building singleport transmitting antennas that shall use improper places (including unspecialized masts) are discussed. Examples of such antennas are listed.
Multiport antennas besides solving antenna problems should provide multiplexing of large number incoherent signals. Short analysis of different ways to perform multiplexing is given. Upsides of scheme-spatial multiplexing which is used everywhere in Branch NIIR – SONIIR are explained.
Sample structure scheme of multiport antenna using scheme-spatial multiplexing is listed. Description of scheme and main antenna ideas are given.
Problems of building circular antenna arrays as part of multiport antennas with tangential and normal emitter orientation are addressed shortly. Most devices developed use normal orientation. Problems of building beamforming networks are discussed. Some devices use LC-networks, most use Butler matrixes. There is a device which uses Butler matrix with port number not being a power of 2. According to the information authors have it is a unique example in the world. Way to form sector-shaped patterns in horizontal plane using beamforming network based on Butler matrix is described (was done on one sample).
High variety of placing circular antenna arrays which are part of multiport antennas been developed and are being used in various regions of our country is mentioned.