GATE 2014 EC (EC3) – Question 34

Electromagnetics · Waveguides and Optical Fibers · 1 mark · Numerical answer

An air-filled rectangular waveguide has cross-section 5 cm × 3 cm. Find TE₂₁ cutoff frequency (MHz).

Practise this question in The GATE Grind →

Show answer and explanation

Correct answer: 7750 to 7850

Explanation

For an air-filled rectangular guide, fcmn=(c/2)√[(m/a)²+(n/b)²]. With a=0.05m,b=0.03m,m=2,n=1, fc=1.5×10⁸√[40²+(100/3)²]=7.81025×10⁹Hz=**7810.25MHz**.