Question

What is the ratio of maximum frequency to minimum frequency if the scaling factor is 0.5 for 5 elements LPDA?

(a) 16

(b) 2

(c) 4

(d) 8

The question was asked in a national level competition.

This question is from Frequency Independent Antenna in portion Frequency Independent Antenna of Antennas

Answer 1

The correct answer is (a) 16

Explanation: The relation between frequency ratio and the scaling factor is given by

\(\frac{f_{max}}{f_{min}} = \frac{1}{τ^{N-1}} \)

\(\frac{f_{max}}{f_{min}} =\frac{1}{τ^{N-1}} =\frac{1}{(0.5)^{5-1}}=2^4=16. \)