The paper presents an analysis of the radiation of dipole antenna excited by polyharmonic signal. It is considered, that relative signal bandwidth defined by:

*

is no less then l (*) and that the first resonant frequency of antenna * is comparable with harmonic component frequencies of exciting signal. It means that *, where f_d are f_g - the lowest and uppermost component frequencies of signal, respectively.

Antenna is modeled as the cascade of two quadrupoles (fig. 1). One of them represents circuit features of antenna (Y_A = 1/Z_A) and the other represents field features of antenna (Z_T). It means that the antenna is analyzed as a spatial- frequency filter.

*

Fig. 1. Equivalent circuit of the dipole antenna

Radiated signals (antenna responses) are computed in time and frequency domains for * = 0 and * = 7 (*, c is the light velocity in vacuum, 2l is the length of dipole antenna), and for several values of τ/T, where τ is the pulse width, T is the signal period.

Method of modelling can be used to describe undesired radiation of desktop equipment.