Abstract:
In order to reduce the size of a microstrip line (1) and to improve the Q-value, the length and width of the microstrip line (1) in the oscillator are greatly decreased. Further, the resonance frequency which would be increased by the reduction in the size of the microstrip line (1) is not increased by virtue of the addition of a capacitance (Cx) connected to one end of the microstrip line (1) to become close to the oscillation frequency of the oscillator. This small sized microstrip (1) renders the size of the oscillation circuit small and gives the characteristics which are equal to those of a dielectric coaxial resonance element.
Abstract:
A method (100) for tuning a voltage controlled oscillator by changing electrical circuit parasitics includes a first step (102) of providing a voltage controlled oscillator circuit on a circuit board and a plurality of different metal lids each having different numbers, sizes and locations of holes. Each different lid presents a different electrical circuit parasitic to the voltage controlled oscillator. In a second step (104), the voltage controlled oscillator frequency is measured, and the frequency shift needed to achieve a desired operating frequency is calculated in a third step (106). In a fourth step (108), a lid is chosen that will present the parasitics needed to provide the amount of frequency shift needed. As a last step (110), the chosen lid is attached to the circuit board to obtain the desired nominal operating frequency from the voltage controlled oscillator.
Abstract:
A miniature microstrip/cavity oscillator which is mechanically tunable over a wide range of microwave frequencies and maintains high frequency stability over changes in temperature. The oscillator consists of a RF (resonant frequency) determining element, a microstrip circuit board means, and a capacitive coupling probe coupling the microstrip circuit board means to the RF determining element. The RF determining element is constructed of various materials with different coefficients of linear expansion to eliminate expansion and contraction effects due to temperature changes.
Abstract:
A voltage-variable capacity diode is coupled through a one-third wavelength transmission line to a resonant cavity. The capacity of the diode is varied by a modulating voltage so as to change the resonant frequency of the cavity, and hence the resonant frequency of an oscillator. The transmission line causes the resonant frequency of the cavity to vary more linearly over a relatively wide band as a function of the modulating voltage.