Design examples
This section gives some working examples to provide insight into the appli- cation's ease of use and specific results which validate its performance.
As a first example, a design at a center frequency of 4.3 GHz is shown. The s parameters for the device are given in the following table:
The microstrip parameters for a microstrip realization are dielectric constant of 10.2, substrate height of 0.100 inches, and open circuit stub terminations.
On this page one can get some insight with respect to design placement on the Smith Chart and stability considerations. Design for specific noise figure is not a factor in this design so that these considerations may guide the choice. A load plane design is chosen.
The load plane page:
The selection bullet gives a normalized load impedance of 0.537+j1.0 ohms corresponding to a load reflection coefficient of 0.6 magnitude at an angle of 81.93 degrees. The output matching network will transform the real load of 50 ½ to this required device load impedance. The input matching network design will transform the real source impedance of 50 ½ into the conjugate of the device input impedance which results when the device is loaded with the specified load impedance.
The microstrip page: The results of the matching networks design for a microstrip realization is shown.
The lumped elements page:
The results page:
Lumped elements:
Typically, the lumped elements realization will exhibit broader band per formance because the transmission line elements have higher Q factor.
An example using a design from Microwave Amplifiers is shown in the fol lowing.
S parameters:
The microstrip parameters for a microstrip realization are dielectric constant of 2.23, substrate height of 0.031 inches, and open circuit stub terminations.
The data input page:
The overview page:
The selection bullet gives a normalized source impedance of 0.682-j0.15 ohms corresponding to a load reflection coefficient of 0.208 magnitude at an angle of 209.89 degrees. This chosen operating condition is for a gain of 11dB and a noise figure of 2.8 dB. The input matching network will transform the real source impedance of 50 ½ to this required device source impedance. The output matching network design will transform the real load impedance of 50 ½ into the conjugate of the device output impedance which results when the device has the specified source impedance.
The microstrip page:
The lumped elements page;
The results page:
Microstrip:
Luimped elements:
References
M. Staloff, Computer-Aided Design and Analysis of Microwave Transistor Amplifiers, Microwave Journal, Vol. 30, No. 5, May, 1987.
S-Parameters, Circuit Analysis and Design, Hewlett Packard Application Note 95.
G. Gonzales, Microwave Transistor Amplifiers Analysis and Design, Prentice-Hall, Inc., Englewood Cliffs, NJ 1984.
T. T. Ha, Solid-State Microwave Amplifier Desgn, Wiley-Interscience, New York, 1981.
R. N. Ghose, Microwave Circuit Theory and Analysis, McGraw-Hill Book Co. Inc., New York, 1963.
Marcus Staloff
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