10-04-2017, 09:15 PM
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Resonator
A resonator is a device or system that exhibits resonance or resonant behavior, that is, it naturally oscillates at some frequencies, called its resonance frequencies, with greater amplitude than at others
It oscillates at specific frequencies because its dimensions are an integral multiple of the wavelength or half-wavelength at those frequencies
Resonators are used to either generate waves of specific frequencies or to select specific frequencies from a signal
In physics and engineering the quality factor or Q factor is a dimensionless parameter that describes how under-damped an oscillator is.
Higher Q indicates a lower rate of energy loss relative to the stored energy of the oscillator; the oscillations die out more slowly.
A system with low quality factor (Q < ) is said to be overdamped.
A system with high quality factor (Q > ) is said to be underdamped.
A system with an intermediate quality factor (Q = ) is said to be critically damped.
S-parameters refer to RF "voltage out versus voltage in" in the most basic sense.
For the S-parameter subscripts "ij", j is the port that is excited (the input port), and "i" is the output port.
Thus S11 refers to the ratio of signal that reflects from port one for a signal incident on port one.
Parameters along the diagonal of the S-matrix are referred to as reflection coefficients because they only refer to what happens at a single port
Off-diagonal S-parameters are referred to as transmission coefficients, because they refer to what happens from one port to another.
- S21 means the response at port 2 due to a signal at port 1 - Let's examine a two-port network. The incident voltage at each port is denoted by "a", while the voltage leaving a port is denoted by "b"
Directional Coupler Insertion Loss (IL) = 10*log(P1/P2) Coupling Factor (CF) = 10*log(P1/P4) Isolation (I) = 10*log(P1/P3) Directivity (D) = 10*log(P4/P3)
-The Magic tee can be used as a power combiner or a divider. -Port 1 is the (sum) port, and is sometimes called the H-plane port. A signal incident on port 1 equally splits between ports 2 and 3, and the resulting signals are in phase. -A signal incident on the difference port splits equally between ports 2 and 3, but the resulting signals are 180 degrees out of phase
A 3 dB, 90 Hybrid coupler is a four-port device that is used either to equally split an input signal with a resultant 90 phase shift or to combine two signals while maintaining high isolation between the ports.
A Horn antenna is used for the transmission and reception of microwave signals. It derives its name from the characteristic flared appearance. The flared portion can be square, rectangular, or conical. The maximum radiation and response corresponds with the axis of the horn. It is usually fed with a waveguide.
A parabolic reflector is a reflective device used to collect or project energy such as light, sound, or radio waves
A spherical wave generated by a point source placed in the focus is transformed into a plane wave propagating as a collimated beam along the axis.
Any incoming ray that is parallel to the axis of the dish will be reflected to a central point, or "focus
Application
Patch antennas
Lightweight,
Inexpensive
Easy to integrate with accompanying electronics
Low fabrication cost
Easily mounted in missiles and satellites
Dual frequency antenna can be made
Resonator
A resonator is a device or system that exhibits resonance or resonant behavior, that is, it naturally oscillates at some frequencies, called its resonance frequencies, with greater amplitude than at others
It oscillates at specific frequencies because its dimensions are an integral multiple of the wavelength or half-wavelength at those frequencies
Resonators are used to either generate waves of specific frequencies or to select specific frequencies from a signal
In physics and engineering the quality factor or Q factor is a dimensionless parameter that describes how under-damped an oscillator is.
Higher Q indicates a lower rate of energy loss relative to the stored energy of the oscillator; the oscillations die out more slowly.
A system with low quality factor (Q < ) is said to be overdamped.
A system with high quality factor (Q > ) is said to be underdamped.
A system with an intermediate quality factor (Q = ) is said to be critically damped.
S-parameters refer to RF "voltage out versus voltage in" in the most basic sense.
For the S-parameter subscripts "ij", j is the port that is excited (the input port), and "i" is the output port.
Thus S11 refers to the ratio of signal that reflects from port one for a signal incident on port one.
Parameters along the diagonal of the S-matrix are referred to as reflection coefficients because they only refer to what happens at a single port
Off-diagonal S-parameters are referred to as transmission coefficients, because they refer to what happens from one port to another.
- S21 means the response at port 2 due to a signal at port 1 - Let's examine a two-port network. The incident voltage at each port is denoted by "a", while the voltage leaving a port is denoted by "b"
Directional Coupler Insertion Loss (IL) = 10*log(P1/P2) Coupling Factor (CF) = 10*log(P1/P4) Isolation (I) = 10*log(P1/P3) Directivity (D) = 10*log(P4/P3)
-The Magic tee can be used as a power combiner or a divider. -Port 1 is the (sum) port, and is sometimes called the H-plane port. A signal incident on port 1 equally splits between ports 2 and 3, and the resulting signals are in phase. -A signal incident on the difference port splits equally between ports 2 and 3, but the resulting signals are 180 degrees out of phase
A 3 dB, 90 Hybrid coupler is a four-port device that is used either to equally split an input signal with a resultant 90 phase shift or to combine two signals while maintaining high isolation between the ports.
A Horn antenna is used for the transmission and reception of microwave signals. It derives its name from the characteristic flared appearance. The flared portion can be square, rectangular, or conical. The maximum radiation and response corresponds with the axis of the horn. It is usually fed with a waveguide.
A parabolic reflector is a reflective device used to collect or project energy such as light, sound, or radio waves
A spherical wave generated by a point source placed in the focus is transformed into a plane wave propagating as a collimated beam along the axis.
Any incoming ray that is parallel to the axis of the dish will be reflected to a central point, or "focus
Application
Patch antennas
Lightweight,
Inexpensive
Easy to integrate with accompanying electronics
Low fabrication cost
Easily mounted in missiles and satellites
Dual frequency antenna can be made