When building broadband amplifiers, very often the design shows unwanted slopes in the amplitude response. Most likely the Gain of the used transistor decreases by Frequency. As this mayst be unwanted in some applications, you must introduce components with a characteristic suiteable to counteract and balance the system. This one uses ready made Equalizers by Mini Circuits to do the job.

The circuit uses three times the GALI-39+, having been chosen for its low Noise Figure of approx. 2.4 dB. And three times an equalizer. Twice of the type EQY-6-63 and once EQY-8-63. The cascade starts with a GALI, as we did not want to worsen the overall Noise Figure by putting attenuation in front of the first amplifier.

The circuit is powered by + 5 Volts and draws approx. 120 mA.

S11, please note that the vertical scale is 5 dB/DIV



S22, please note that the vertical scale is 5 dB/DIV



S21 - we think that's a beautiful slope (first attempt !!!)


All measured with a hp8753, 6 GHz VNA.

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