Saturday, 28 January 2017
Monday, 16 January 2017
MIC EXPERIMENT-7
EXPERIMENT-7
Aim:
Design of class AB Amplifier using Keysight
ADS.
Theory:
To overcome crossover distortion, the biasing is adjusted
to just overcome the VBE of the ransistors. In class AB operation, the
push-pull stages are biased into slight conduction, even when no input signal
is present. This can be done with a voltage-divider and diode arrangement, as
shown
Class AB
amplifier:
Using equal values of R1 and R2 the positive and negative
supply voltages forces the voltage at point A
to equal 0 V and eliminates the need for an input coupling capacitor.
Desin In ADS:
Simulation Result:
Simulation Result:-
Conclusion:MIC EXPERIMENT-6
EXPERIMENT-6
Aim:-
Design of Rectangular
Microstrip Patch
Antenna using Keysight ADS. Theory:
A patch antenna is a narrowband, wide-beam antenna fabricated by etching the antenna element
pattern in
metal trace bonded
to an insulating dielectric substrate, such as a printed circuit board, with a continuous metal layer bonded to the opposite side of the substrate which forms
a ground
plane. Common microstrip antenna
shapes are
square,
rectangular, circular
and elliptical, but any continuous shape is possible. Some patch antennas do not use a dielectric
substrate and instead are made of a metal patch mounted above a ground plane using dielectric spacers; the resulting structure is less rugged but has a wider bandwidth. Because such antennas
have a very low profile, are mechanically rugged and can be shaped to conform to the curving
skin of a vehicle, they are often mounted on the exterior of aircraft and spacecraft, or are
incorporated
into mobile radio communications devices.
Rectangular
Patch:
The most commonly employed microstrip
antenna is a rectangular patch which looks like a
truncated microstrip transmission line. It is approximately of one-half wavelength long. When air
is
used
as the dielectric substrate, the length
of
the
rectangular
microstrip
antenna is approximately one-half of a free-space wavelength. As the antenna is loaded with a dielectric as its
substrate,
the
length
of
the
antenna decreases as
the
relative dielectric constant of
the
substrate increases. The resonant length of the antenna
is
slightly shorter because of
the
extended electric "fringing fields" which increase the electrical length of the antenna
slightly. An early model of the microstrip antenna is a section of microstrip
transmission line with equivalent loads on either
end to represent
the
radiation loss.
Fig. Microstrip
patch
Antenna
Design Equations:-
Resonant frequency (fr)
of the rectangular microstrip
patch is given by
Effective Dielectric constant
Effective length of patch
Width of patch
Design In ADS:
Layout:-
Simulation Result:- Conclusion:-
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