Question

Quality factor is defined as ________

(a) \(2π×\frac{energy \,radiated\, per\, cycle}{Total\, energy\, stored\, by\, antenna}\)

(b) \(4π×\frac{Total \,energy \,stored \,by\, antenna}{energy\, radiated\, per \,cycle}\)

(c) \(4π×\frac{energy \,radiated\, per \,cycle}{Total \,energy\, stored \,by \,antenna}\)

(d) \(2π×\frac{Total \,energy\, stored\, by \,antenna}{energy\, radiated \,per \,cycle}\)

The question was asked in final exam.

This intriguing question comes from Antenna Bandwidth topic in portion Antenna Parameters of Antennas

Answer 1

Correct answer is (d) \(2π×\frac{Total \,energy\, stored\, by \,antenna}{energy\, radiated \,per \,cycle}\)

The explanation: Quality factor Q=\(2π×\frac{Total \,energy\, stored\, by \,antenna}{energy\, radiated \,per \,cycle}\). Higher Q antennas will have low bandwidth.