Page 448 - Complete Wireless Design

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Wireless Issues 447

will automatically display the possible LC matches (in L network form) along
with the parallel equivalents, the VSWR, and the return loss.
Impedance Matching Network Designer by John Wetherell is a free online
program that assists in the rapid design of 16 various matching networks;
just enter the source’s resistance and reactance, with the frequency of inter-
est and the desired circuit Q, and the program will display the values of the
appropriate matching topologies. It is available online at http://www-
inst.EECS.Berkeley.EDU/ wetherel/rftoolbox/matcher2.html.
Motorola’s Impedance Matching Program (MIMP) for power amplifiers per-
mits the load and source impedances to be specified, then lets the user place
lumped or distributed elements between this source and load, enabling the
viewing of the quality of the resultant match on the program’s Smith chart and
return loss graph. It is obtainable free on Motorola’s Web site.
Multfreq, by Cezar A. Carioca et al., is available free (through Applied
Microwave and Wireless Magazine Online), and will automatically design a
lumped or distributed diode frequency multiplier of the varactor or Schottky
type. Since this program will display the distributed filter structures neces-
sary for the multiplier circuits, along with the filter’s dimensions and fre-
quency response, a distributed bandpass and low-pass filter can also be
designed with this one-of-a-kind program.
MixSpur, by The Engineer’s Club, is a low-cost program that will graphical-
ly, and in tabular format, display the spurious output frequencies and their
amplitude as emitted from a mixer and LO stage. A must for receiver and
transmitter design to confirm that both in-band and out-of-band mixer-gener-
ated spurious signals are below specifications—or that more filtering, a new
LO frequency, or a different mixer may be required. It is available for sale at
http://www.engineers.com/mxrspur.htm.
PUFF, a microwave program by Caltech’s David Rutledge, Scott W. Wedge,
Richard Compton, and Andreas Gerstlauer, is a linear (S-parameter) simula-
tor that permits a designer to simulate lumped and distributed circuits, and
then plot gain, return loss, and phase in a fully graphical format. Indeed, if an
engineer does not possess a more expensive, high-end wireless software pack-
age, such as AWR’s Microwave Office, Eagleware’s Genesys, or HP’s EEsof, for
example, then PUFF is indispensable. The full version of PUFF is included
with this book on CD ROM.
On a system design level, Kirt Blattenberger’s low-cost RF Workbench should
be purchased, as it will assist the designer to define the specifications of a trans-
mitter or receiver’s amplifiers, filters, and mixer stages, and then view the resul-
tant spectrum in the frequency domain. RF Workbench will not only permit you
to see if the system’s sum frequency or LO feedthrough will be troublesome, but
also, if any stage is going into compression, what the system’s gain, P1dB, IP3,
P , and NF values are. This program checks whether any mixer spurs are in or
OUT
out of band (and what their amplitudes may be), calculates the complete trans-
mitter-to-receiver path, creates a frequency and cascaded amplitude budget plan,
and does other functions too numerous to mention. Available on the Web.

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