High Order Harmonic Oscillators in Microwave and Millimeter-wave ...
High Order Harmonic Oscillators in Microwave and Millimeter-wave ...
High Order Harmonic Oscillators in Microwave and Millimeter-wave ...
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1 Introduction<br />
Problems of the conventional<br />
high frequency oscillators<br />
Selectively Enhanced <strong>Harmonic</strong> Oscillator<br />
(This work)<br />
Advantage<br />
Complicated structure<br />
Low output power<br />
External circuits<br />
(filter, mixer, amplifier, etc.)<br />
Undesired harmonics<br />
Phase noise<br />
Simple structure<br />
<strong>High</strong> output power<br />
No external circuit<br />
Low noise<br />
Fig. 1.2: Problem of the conventional oscillators <strong>and</strong> advantages of the proposed SEHO.<br />
filter<br />
amplifier<br />
f<br />
f<br />
f<br />
(a) Conventional harmonic oscillator<br />
(b) Selectively Enhanced <strong>Harmonic</strong> Oscillator<br />
f<br />
Fig. 1.3: Comparison of the conventional harmonic oscillator <strong>and</strong> the proposed SEHO.<br />
<strong>and</strong> undesired harmonics are suppressed by an RF filter. The amplitude of the desired<br />
signal is enhanced by a high frequency amplifier. Through the filter <strong>and</strong> the amplifier, the<br />
noise performance becomes worse due to the loss of the filter <strong>and</strong> the noise of the amplifier.<br />
The other up conversion or down conversion technologies also need RF or optical filters,<br />
mixers <strong>and</strong> amplifiers as well as the harmonic oscillator.<br />
3
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