Study of Thermal Noise Generated in a Vivaldi Antenna Using the Improved Wheeler Cap Method

Efficiency measurement of 1-D connected array using the Improved Wheeler Cap method

“…In this work, we extend our previous work [8] to measurement of connected arrays (as opposed to a single array element). Direct IWC measurement of large PAF is not promising since a very large (in terms of wavelength) enclosure is required.…”

“…Again, when Γ F S L = 0 (ideal-no reflection) IWC efficiency is virtually exact and for RL abs > 30 dB (easily achievable with pyramidal absorbers [12]) measurement uncertainty and accuracy of < 0.5% (for target η ≈ 97% [13]) is achieved for b F S ≈ 12 to 15 cm (k 0 b F S ≈ 2.5 to 3.1). For each k 0 b value, a set of Γ W Cap L data for circle fitting [8], [14] was generated by perturbing b by ±10%. Note that measurement uncertainties diminish with higher efficiency.…”

“…Efficiency measurement of a Vivaldi element for a phase array feed (PAF) demonstrator [7] has been discussed in [8] where accuracy and repeatability of approximately 1% (or better, on average) was reported.…”

Efficiency Measurement of Connected Arrays Using the Improved Wheeler Cap Method

“…Its application to radio astronomy antennas, such as the Vivaldi phased array feed (PAF) element [2], has been discussed in [3] where accuracy and repeatability estimates of less than 1% have been demonstrated. However, that work concerns only a single Vivaldi element as opposed to the connected array which makes up the PAF.…”

“…As a result, cavity resonances more numerous than may be effectively removed are expected to overwhelm the data [3], [4] 1 modification to the WCap for a connected array as depicted in Fig. 1 for a 1-D array and Fig.…”