Calculation of Site Attenuation for Calculable Dipole Antennas

Abstract

This paper presents a method for calculating the site attenuation (SA) of an open-area test site (OATS) for a pair of calculable dipole antennas with a 3-dB hybrid balun in the frequency range of 30 MHz to 1 GHz. The SA was directly derived using the concept of power mismatch and dissipative loss from the SA measurement system instead of the concept of substitution loss. Two types of SA formulas using the power loss concept on the treatment of the OATS are presented. The first is the SA formula related to knowing only the value of the SA. The other is the SA formula that analyzed the effects of each part of the SA. Additionally, the constituent losses of the SA measurement system are discussed using the derived SA formula. The analysis of the results showed that the SA could be successfully characterized individually from the loss of the OATS. It also showed that SA is expressed as two kinds of losses: the balanced portmismatch losses of transmit and receive baluns and the half-space dissipative loss. The resultant SA showed good agreement with the results calculated from the S-parameters as well as with the measured results.

Calculation of Normalized Site Attenuation for Calculable Dipole Antennas

“…The CSA is defined as the minimum site power loss between the two antennas, including the baluns, as the RX antenna scans over a given height range. The CSA can be expressed in decibels in a simplified form [21]:…”

“…In the calculation of the theoretical NSA of an ideal OATS from Eqs. (3), (13), and ( 14), the TX and RX antenna system analysis is required, in which case a thin-wire kernel approxima-tion with a segment length of 0.0125λ is used for the piecewise sinusoidal Galerkin's methods of moment analysis, as presented in [19][20][21]. The dipole radius (𝑎 = 3.175 mm; 30 MHz f 300 MHz and 𝑎 = 0.794 mm; 300 MHz f 1 GHz ) was chosen to be less than 0.007λ (thin-wire approximation).…”

“…Theoretical NSA values for an ideal OATS, using calculable dipole antennas (CalDAs) with a 3-dB 180° hybrid balun, are considered in the frequency range of 30 MHz to 1 GHz. The CalDAs with a 3-dB hybrid balun were developed for the field strength standard [16][17][18][19][20][21]. To calculate the theoretical NSA values, the CSA of the OATS and AFs of the TX and RX antennas are required.…”

“…Therefore, the NSA calculation is based on this substitution loss concept. However, another study [21] directly derived a new equation for an SA measurement system using power mismatch and dissipative loss, instead of substitution loss.…”

“…In this paper, the theoretical NSA values for an ideal OATS for a pair of CalDAs are newly calculated using power mismatch and dissipative loss, as previously shown for the CSA calculation [21]. In the calculation of the theoretical NSA, the TX and RX antenna system analysis is required, in which case piecewise sinusoidal Galerkin's methods of moment are used.…”