GATE EC 2016 Set 1 — Question 65
Go beyond PYQs with Success TrackerAI-powered personalised practice and doubt support. Unlimited practice on eligible plans; AI usage limits apply.MCQ+2 / -0.67MediumRadiation PatternAntennasElectromagneticsGain, Directivity & Radiation Resistance
Electromagnetics → Antennas → Gain, Directivity & Radiation Resistance
Last updated
Question
The far-zone power density radiated by a helical antenna is approximated as:The radiated power density is symmetrical with respect to and exists only in the upper hemisphere: ; ; is a constant. The power radiated by the antenna (in watts) and the maximum directivity of the antenna, respectively, are
Correct answer
(B) 1.256C₀, 10dB
Solution
The total power radiated by the antenna is calculated by integrating the power density over the surface of a hemisphere (since the field only exists in the upper hemisphere):The maximum directivity is given by:where is the radiation intensity. The maximum value occurs at .Converting to decibels:Therefore, the power radiated is and the maximum directivity is .
Continue learning with Success Tracker
A step still unclear? Work through it with support
Use Success Tracker to ask about the reasoning, then try another GATE EC question to check your understanding.
AI-powered practice· Unlimited practice on eligible plans
- PYQs with solutions
- Attempt available previous-year questions, then compare your reasoning with the worked solution. Coverage varies by stream.
- Practice that adapts
- Choose a topic, work on weaker areas and bookmark questions to revisit. Your attempts feed your progress tracking.
- AI doubt support
- Ask follow-up questions about a step or concept while practising, instead of stopping at the final answer.
Unlimited practice is available on eligible plans. Free practice and AI usage have limits; check the current plan allowances before choosing.
This page stays readable without an account. AI responses can be wrong; check them against the solution and source material.
More questions on Antennas
2026 Set 1 Q21Consider the Friis' transmission equation , where…2026 Set 1 Q24The electric field of a monochromatic plane wave travelling in a lossless isotropic and homogenous…2026 Set 1 Q28Which option(s) represents/ represent the dielectric loss tangent of a substrate?2026 Set 1 Q33The cutoff frequency (in GHz) for the dominant mode of an air-filled rectangular…2026 Set 1 Q34For a lossless passive two-port network, and intersect at -3 dB. For a lossy…