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```					Radio Frequency Transceiver
Design

Heidi L. Lagares
Introduction

   Microwave engineering involves circuit analysis
and design, in contrast to the field theory
orientation of a generation ago.

   Microwave Engineering is not only apply
sophisticate mathematics.

   A transceiver is a combination
   Some are design to allow reception of
signals during transmission periods.
   An RF transceiver is propose as an
alternative to test design through a wireless
Block Diagram of a RF transceiver

   RF is a term that refers to alternating current
(AC) having characteristics such that, if the
current is input to an antenna, an
electromagnetic (EM) field is generated
suitable for wireless communications.
   Examples: Cordless and cellular telephone,
satellite communications systems.
Analysis

   The analysis of RF transceiver will be
performed using electromagnetic simulator.
   The design will resonate at 5.85 GHz, and
with a bandwidth of 125 MHz.
–   Maximum Gain Amplifier
–   Low Noise Amplifier
–   Mixer
Maximum Gain Amplifier

   Amplification is one of the most basic and
prevalent communication circuit functions.

   The overall gain of an amplifier will be
controlled by the gains GS and GL (input gain
and out gain respectively).
Maximum Gain Amplifier Results

   The maximum gain
amplifier has gain of
15.6 dB.
Low Noise Amplifier

   An important design for amplifier is the noise
figure.

   A low noise was designed with a GaAs field
effect transistor operating at the desired
frequency.
Low Noise Amplifier Results

   As the graph shows,
the amplifier gain is
13.7dB.
   S11 (black marker)
is at -4.7 dB.
Mixer

   Mixers use nonlinear device to achieve
frequency conversion of an input signal.
   When signals of different frequencies are
applied to such a device, the output contains
not only the original frequencies but also
frequencies equal to the sum and difference
of the original frequencies.
Structure of the mixer design

   This is the basis structure of the mixer
design.

RF                       Matching
Rat                                     IF
network          LP Filter
LO           Race
(180 hybrid)   Matching
network

Singly Balanced Mixer
Mixer Design

RF     IF

fRF        LO
f RF  f LO   f RF  f LO

fLO
Mixer Results

Spectrum at IF port, dBm
   The conversion gain                 60

is -25dB (the first                 40

IF_spectrum
20
impulse at 0GHZ)                     0

-20

-40
0   2     4      6        8   10   12
freq, GHz
Conclusion

   Researchers, designers and students work in
the development of complex data processing
and modulation circuits using DSP
development kits.
   They should test their designs in a more real
environment and transmit and receive data
acoustically.
Questions?

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 views: 6 posted: 5/17/2012 language: English pages: 17