High gain is not achievable at microwave frequencies using BJT amplifiers because:

Related MCQs

• In conventional amplifiers, a flat gain response is achieved at the cost of reduced gain. But this drawback can be overcome by using:
• Klystron amplifiers have high noise output as compared to crossed field amplifiers.
• Microwave tubes are power sources themselves at higher frequencies and can be used independently without any other devices.
• The production of power at higher frequencies is much simpler than production of power at low frequencies.
• Gain of power amplifiers                      with increase in operating frequency.
• Magnetrons are microwave devices that offer very high efficiencies of about 80%.
• Distributed amplifiers offer very high
• Reactive multipliers have a disadvantage that they cannot be used at very high frequencies and they become less efficient.
• In a microwave oscillator, a load of 50+50j is connected across a negative resistance device of impedance -50-50j. Steady state oscillation is not achieved in the oscillator.
• In transistor oscillators, FET and BJT are used. Instability is achieved by: