254 pages | 2 Color Illus. | 170 B/W Illus.
Expanding the range of antenna frequency is the main objective of this book. Solutions proposed are based on the development of new theoretical methods for analyzing and synthesizing antennas. The book shows that concentrated capacitive loads connected along linear and V-antennas provide a high level of matching with a cable over a wide frequency range and improves directional characteristics of antennas, i.e. increases the communication distance.
New theoretical methods are proposed for analysis and synthesis of antennas under consideration: 1) method of calculating directional characteristics of radiators with a given current distribution, and 2) method of electrostatic analogy for calculating mutual and total fields of complex multi-element radiating structures. These methods allow us to obtain optimal directional characteristics for director-type antennas (arrays of Yagi-Uda) and log-periodic antennas with concentrated capacitances and show that use of capacitors makes it possible to extend the frequency range of the director antennas and to decrease dimensions of the log-periodic antennas
Multi-element (flat and three-dimensional) self-complementary antennas with different variants of connecting generator poles and cable wires to antenna elements are proposed, which improves the matching with a cable. Characteristics of flat structures are compared with characteristics of volume structures: conical, parabolic, and located on a pyramid edges.
The book describes new versions of transparent antennas, antennas for cellular communication, multi-tier and multi-radiator antennas, and much more.
Table of contents
PART 1. WIDE-BAND ANTENNAS
Radiators with distributed loads
Radiators with non-zero (impedance) boundary conditions. Constant surface impedance
An impedance long line as an approximate analog of an impedance radiator
Radiator with a surface impedance varying as coordinates function along its length
How mistakes are created
Radiators with concentrated loads
Capacitive loads. An in-phase current distribution along a radiator
Creating in-phase current using a method of an impedance line
Creating in-phase current using a method of a metallic long line with loads
Optimization of antenna characteristics
Optimal matching of linear radiators with constant capacitive loads
Creating a required current distribution in a given frequency range
Reducing an influence of nearby metal superstructures
An optimal matching of V- radiators with constant capacitive loads
Directional characteristics of radiators with capacitive loads
Calculating the directional patterns of radiators with a given current distribution
Method of electrostatic analogy
Decreasing dimensions of log-periodic antennas
Adjustment of characteristics of self-complementary antennas
Volume self-complementary radiators
Self-complementary radiators on a conic surface
Self-complementary radiators on a parabolic surface
Antenna on a pyramid Edges
Self-complementary antennas with rotation symmetry
Procedure of calculating flat self-complementary antennas
Three-dimensional antennas with rotation symmetry
PART 2. MULTIFREQUENCY ANTENNAS
Electrically related long lines, parallel to metal surface.
Multiconductor structures of wires with identical wires.
Meandering loads of wire antennas
Voltages and currents in meandering loads.
Folded antennas, perpendicular to metal surface.
Structures with wires of different length and diameters.
Losses in the ground.
Impedance folded radiators
Multi-folded antennas, perpendicular to metal surface.
Principle of operation and method of calculation
Electrical characteristics of multi-folded radiators
Using multi-folded radiators in compensation devices
Multi-wire and multi-radiator antenna
Multitiered and log-periodic coaxial antennas
Log-periodic coaxial antennas
Antenna with arbitrary single load.
Field of a rectangular loop