10 Questions
The microwave spectrum is usually defined as electromagnetic energy ranging from approximately ______ GHz to 1000 GHz in frequency.
1
The L band frequency range is from ______ to 2 GHz.
1
The C band frequency range is from ______ to 8 GHz.
4
The Ka band frequency range is from ______ to 40 GHz.
26.5
Waveguides can be generally classified as either ______ waveguides or dielectric waveguides.
metal
Waveguides are structures used to guide ______ waves from point to point.
electromagnetic
The fundamental characteristics of waveguide and transmission line waves are quite ______.
different
The differences in waveguide and transmission line waves result from the basic differences in ______ for a transmission line and a waveguide.
geometry
Metal waveguides normally take the form of an enclosed ______ conducting metal pipe.
conducting
The dielectric waveguide consists of ______ only and employs reflections from dielectric interfaces to propagate the electromagnetic wave along the waveguide.
dielectric's
Study Notes
Commercial Implementations
- Commercial implementations of wireless access technology operate in the 2.3 GHz, 2.5 GHz, 3.5 GHz, and 5.8 GHz ranges.
Wide Area Mobile Broadband Wireless Access
- MBWA protocols, such as IEEE 802.20 and ATIS/ANSI HC-SDMA (e.g., iBurst), operate between 1.6 GHz and 2.3 GHz to provide mobility and in-building penetration characteristics similar to mobile phones but with greater spectral efficiency.
Microwave Applications
- Microwave frequencies are used in:
- Cable TV and internet access on coaxial cable
- Broadcast television
- Mobile phone networks (e.g., GSM)
- Microwave radio broadcasting and telecommunication transmissions
- Television news transmission from remote locations
- Radar technology for detecting range, speed, and other characteristics of remote objects
- Radio astronomy
Microwave Sources
- Vacuum tube-based devices:
- Operate on the ballistic motion of electrons in a vacuum under the influence of controlling electric or magnetic fields
- Include magnetron, klystron, travelling wave tube (TWT), and gyrotron
- Solid-state sources:
- Field-effect transistor
- Tunnel diodes
- Gunn diodes
- Maser (Microwave Amplification by Stimulated Emission of Radiation): a device similar to a laser, operating at microwave frequencies
Communication
- Microwave point-to-point links were used for long-distance telephone calls before the advent of fiber optic transmission
- Frequency division multiplex was used to send up to 5,400 telephone channels on each microwave radio channel
- Wireless LAN protocols, such as Bluetooth and IEEE 802.11, use microwaves in the 2.4 GHz ISM band
- Licensed long-range Wireless Internet Access services use the 3.5–4.0 GHz range
- Metropolitan Area Networks: MAN protocols, such as WiMAX (Worldwide Interoperability for Microwave Access), operate between 2 to 11 GHz
Microwave Frequency Bands
- Microwave frequency bands, as defined by the Radio Society of Great Britain (RSGB), are:
- L band: 1 to 2 GHz
- S band: 2 to 4 GHz
- C band: 4 to 8 GHz
- X band: 8 to 12 GHz
- Ku band: 12 to 18 GHz
- K band: 18 to 26.5 GHz
- Ka band: 26.5 to 40 GHz
- Q band: 30 to 50 GHz
- U band: 40 to 60 GHz
- V band: 50 to 75 GHz
- E band: 60 to 90 GHz
Waveguides
- Waveguides are structures used to guide electromagnetic waves from point to point
- Types of waveguides:
- Metal waveguides: enclosed conducting metal pipes
- Dielectric waveguides: use dielectric interfaces to propagate the electromagnetic wave
This quiz covers various wireless broadband technologies including Wide Area Mobile Broadband Wireless Access and Microwaves. It also touches on Cable TV and Internet access on coaxial cable.
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