Boris Levin

The Development of a Cellular Phone Antenna with Small Irradiation of Human-Organism Tissues

The method put forward here is to reduce undesirable irradiation using an auxiliary radiator of low power. Calculations show that an arrangement with an additional radiator reduces irradiation by a factor of three to four. The structure and magnitude of the field in the far zone preserve their quality of communication with the correspondents (base stations) in all directions.

Directional properties of linear and v-antennas

The method for calculating directional characteristics of thin antennas with large dimensions: directional patterns, directivity, pattern factor is proposed. The analytical expressions are determined, and characteristics of metal dipoles, V-dipoles and analogous in-phase radiators are calculated. The importance of accounting the pattern factor for the estimate of a communication range is shown. The advantage of in-phase radiators is demonstrated. The possibility of an employment of the given radiators as elements of directional antennas and antenna arrays is considered.

Directivity of thin antennas

The analytical expressions are obtained, and the method of calculating directional patterns of thin antennas with large dimensions was proposed. Directivity of dipoles, V-dipoles and in-phase radiators of similar types were calculated. The importance of accounting the magnitude PF for the estimate of a communication range was demonstrated.

Cellular Phone Antenna with a Small Irradiation of the Human Head

A compensation method for reducing the irradiation of the head of a cellular phone user without degradation of the far field is analyzed. This method uses two radiators that are located in the near region of each other, and create a weak field area in this region. The impacts of the mutual coupling between closely located radiators on the input impedance, current distribution, and fields of the radiators are studied. It is shown that the structure of two closely spaced monopoles is equivalent to the superposition of two basic structures: a two-wire open-ended line, and a single monopole. The shape and dimensions of the dark spots and the irradiation-reduction factor are determined. To facilitate the field calculations in the near zone of the antennas, a method based on replacing a piecewise-homogenous medium by an equivalent homogenous medium is used. The calculations and the experimental results in the presence of the head qualitatively agreed.

Dark spot shift along a vertical line

Use of compensation method for creation of weak field area located above an antenna feed point is considered. Structure comprising two additional radiators, which are placed symmetrically with respect to the straight line passing through a main radiator feed point and a dark spot center and create the same fields, is presented.

Director antenna with in-phase currents

The method of calculating directional characteristics of director antenna: directional patterns, directivity, pattern factor is proposed. The analytical expressions are determined, and characteristics of antennas with metal dipoles, with V-dipoles and with analogous in-phase radiators are calculated. The advantage of in-phase radiators is demonstrated. It is shown that the director antennas with linear and V-radiators with in-phase current distribution provide high directivity in a wide frequency range. The task of optimization of considered antennas by methods of mathematical programming is stated.

Variants of volume self-complementary antennas

Variants of volume self-complementary antennas (conic, parabolic et al.) are considered. Method of their analysis is described. Electrical characteristics depending on frequency are calculated and measured in models. Properties of different volume antennas are compared with each other and with properties of flat self-complementary antennas. It is shown that the volume self-complementary antennas allow operating at longer wavelengths and that increasing the generatrix length causes an improvement of the electrical characteristics.

A monopole with raised feed point

The field of a finite length monopole whose feed point is raised (sleeve antenna) is calculated. Its behavior is similar to a dipole with two feed points. The mutual coupling between closely located radiators of this type, when used in the compensation method, is considered.

Log-periodic antennas with in-phase currents

The approximate method of calculating directional characteristics of log-periodic antenna: directional patterns, directivity, and pattern factor is proposed. The analytical expressions are determined, and characteristics of antennas with straight metal dipoles and with in-phase radiators of the same dimensions are calculated. The advantage of using in-phase radiators is demonstrated. It is shown that the log-periodic antennas of radiators with in-phase current distribution allow to decrease the antenna length and to provide the high directivity in a wide frequency range. The problem of optimization of considered antennas by methods of mathematical programming is stated.

Theorem on oscillating power

The article tells about the contribution of Vainsteins theorem in the development of electromagnetic theory. In accordance with this theorem the total power of electromagnetic field consists of active and oscillating components. The first magnitude is the active part of the power flow, equal to its average value. The second magnitude is the oscillating part of the power flow. It oscillates in time with a double frequency. An example of a problem, which has been solved by means of this theorem, - radiation of an antenna - is considered in the paper.