09-03-2012, 03:56 PM
short rage wireless communication
[attachment=18173]
Developers, manufacturers and marketers of products incorporating
short-range radio systems are experts in their fields—security, telemetry,
medical care, to name a few. Often they add a wireless interface just to
eliminate wires on an existing wired product. They may adapt a wireless
subsystem, which is easy to integrate electrically into their system, only
to find that the range is far short of what they expected, there are frequent
false alarms, or it doesn’t work at all. It is for these adapters of
wireless subsystems that this book is primarily intended.
Other potential readers are curious persons with varied technical
backgrounds who see the growing applications for wireless communication
and want to know how radio works, without delving deeply into a
particular system or device. This book covers practically all aspects of
radio communication including wave propagation, antennas, transmitters,
receivers, design principles, telecommunication regulations and
information theory. Armed with knowledge of the material in this book,
the reader can more easily learn the details of specialized radio communication
topics, such as cellular radio, personal communication systems
(PCS), and wireless local area networks (WLAN).
Graphs
A couple of the worksheets have graphs. If you want to find a
particular coordinate and the resolution of the axes is not sufficient,
click on the graph with the right mouse button. Click on Trace. Move
the cursor on the plot and see the coordinates in the Trace window.
Units of Measure
One of the special features of Mathcad is the ease of using units of
measure. You don’t have to use any conversion factors when changing
units. For example, if the default unit of length in a yellow data input
expression is cm (centimeters) and you prefer to enter your data in
inches, simply insert the number of inches, then replace “cm” with “in.”
Similarly, the units of measure in the blue solution expressions can also
be replaced.
Matching.mcd — Impedance Matching
This worksheet presents several topologies for matching functional
blocks of a radio circuit — antenna to receiver input, transmitter final
stage to antenna, and matching between RF amplifier stages, for example.
R1 is the resistance seen looking into the network when it is
terminated by R2. If a resistance R1 is connected to the left side, then
the resistance looking into the right side will be R2. Circuits (1) and (2)
each have only one solution for a pair of values R1 and R2, whereas in
circuits (3) and (4) the values of the matching components depend on
the value chosen for Q.
Patch.mcd — Microstrip Patch Antennas
You can design a square half-wave microstrip patch antenna using
this worksheet. The formulas account for the “fringing distance,” which
makes the patch length somewhat smaller than a half wavelength in the
board. A result of the worksheet is the impedance at the center of a
board edge to which you have to match the input impedance of a receiver
or output impedance of a transmitter. This matching is usually
done by printed microstrip distributed components. If you want to match
directly to a coaxial cable, solder the cable’s shield to the groundplane
on the opposite side of the board. Connect the center connector through
a via insulated from the groundplane to the patch at the distance “x”
from the center, which is displayed as a result in the last section of the
worksheet.
[attachment=18173]
Developers, manufacturers and marketers of products incorporating
short-range radio systems are experts in their fields—security, telemetry,
medical care, to name a few. Often they add a wireless interface just to
eliminate wires on an existing wired product. They may adapt a wireless
subsystem, which is easy to integrate electrically into their system, only
to find that the range is far short of what they expected, there are frequent
false alarms, or it doesn’t work at all. It is for these adapters of
wireless subsystems that this book is primarily intended.
Other potential readers are curious persons with varied technical
backgrounds who see the growing applications for wireless communication
and want to know how radio works, without delving deeply into a
particular system or device. This book covers practically all aspects of
radio communication including wave propagation, antennas, transmitters,
receivers, design principles, telecommunication regulations and
information theory. Armed with knowledge of the material in this book,
the reader can more easily learn the details of specialized radio communication
topics, such as cellular radio, personal communication systems
(PCS), and wireless local area networks (WLAN).
Graphs
A couple of the worksheets have graphs. If you want to find a
particular coordinate and the resolution of the axes is not sufficient,
click on the graph with the right mouse button. Click on Trace. Move
the cursor on the plot and see the coordinates in the Trace window.
Units of Measure
One of the special features of Mathcad is the ease of using units of
measure. You don’t have to use any conversion factors when changing
units. For example, if the default unit of length in a yellow data input
expression is cm (centimeters) and you prefer to enter your data in
inches, simply insert the number of inches, then replace “cm” with “in.”
Similarly, the units of measure in the blue solution expressions can also
be replaced.
Matching.mcd — Impedance Matching
This worksheet presents several topologies for matching functional
blocks of a radio circuit — antenna to receiver input, transmitter final
stage to antenna, and matching between RF amplifier stages, for example.
R1 is the resistance seen looking into the network when it is
terminated by R2. If a resistance R1 is connected to the left side, then
the resistance looking into the right side will be R2. Circuits (1) and (2)
each have only one solution for a pair of values R1 and R2, whereas in
circuits (3) and (4) the values of the matching components depend on
the value chosen for Q.
Patch.mcd — Microstrip Patch Antennas
You can design a square half-wave microstrip patch antenna using
this worksheet. The formulas account for the “fringing distance,” which
makes the patch length somewhat smaller than a half wavelength in the
board. A result of the worksheet is the impedance at the center of a
board edge to which you have to match the input impedance of a receiver
or output impedance of a transmitter. This matching is usually
done by printed microstrip distributed components. If you want to match
directly to a coaxial cable, solder the cable’s shield to the groundplane
on the opposite side of the board. Connect the center connector through
a via insulated from the groundplane to the patch at the distance “x”
from the center, which is displayed as a result in the last section of the
worksheet.