- 2079 Bhadra · 3+3 marks
Circuit behavior and microwave band classification
Short answer
Low-frequency circuits are lumped with negligible parasitics, skin effect and radiation; microwave circuits are distributed, need matching, and suffer strong skin effect and radiation. IEEE bands: L 1-2 GHz GPS, S 2-4 Wi-Fi/radar, C 4-8 satellite TV, X 8-12 military radar, Ku 12-18 DTH, K 18-27 police radar, Ka 27-40 5G/satellites, V 40-75 WiGig, W 75-110 automotive radar.
Compare the behavior of circuits for Low frequency/Conventional and RF/Microwave bands. Classify microwave frequency band and its application in major areas.
Behaviour of circuits: low frequency vs RF/microwave
| Aspect | Low frequency | RF/Microwave |
|---|---|---|
| Size vs λ | Much smaller | Comparable |
| Model | Lumped R, L, C | Distributed lines and fields |
| Wires | Ideal connections | Transmission lines with phase delay |
| Parasitics | Ignored | Lead L and stray C dominate |
| Skin effect | Negligible | Strong; loss rises as √f |
| Radiation | Negligible | Discontinuities radiate |
| Parameters | Z, Y, h | S-parameters |
| Matching | Rarely needed | Essential, otherwise reflections and VSWR |
Classification of microwave bands and applications (IEEE letter bands)
| Band | Range (GHz) | Major applications |
|---|---|---|
| L | 1–2 | GPS, GSM-1800, satellite phones |
| S | 2–4 | Wi-Fi 2.4 GHz, ovens, weather and ATC radar |
| C | 4–8 | Satellite TV (6/4 GHz), Wi-Fi 5 GHz, links |
| X | 8–12 | Military and marine radar, space probes |
| Ku | 12–18 | DTH TV, VSAT |
| K | 18–27 | Police radar, short links |
| Ka | 27–40 | HTS satellites, 5G mm-wave |
| V | 40–75 | 60 GHz WiGig, inter-satellite links |
| W | 75–110 | 77 GHz automotive radar, imaging |
✓ Answer checked by Claude Opus 5.5 (high effort)
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