Wide frequency range sine wave VCO with a tunable inductor and capacitor

Nonlinear Magnetic Properties of Mn-Modified Ba<tex>$_3$</tex>Co<tex>$_2$</tex>Fe<tex>$_23$</tex>O<tex>$_41$</tex>Hexaferrite

“…5, it is clear that increased on increasing Mn content, from % for reaching maximum at % for , and then decreased with further substitution. The loss tangent behaved in exactly the opposite manner to that of the tunability, which is normal behavior for inductors that the loss tangent of an inductor is approximately in inverse proportion to the inductance [4]. Table I gives the inductance tunability of samples sintered at various temperatures with various compositions.…”

“…Snoek indicated [9] that the product of the initial permeability and cutoff frequency is limited by the inherent properties of the ferrite material (4) where is the initial permeability, is the cutoff frequency, is the saturation magnetization, and is a constant. However, when a ferrite inductor tunes, the dc flux inside the material not only lowers the permeability and thus the inductance, but also extends the maximum operating frequency.…”

“…Compared with varactor diodes, which are commonly used to tune an tank and have limited frequency-tuning range, tunable inductors make wide-frequency range operation possible. Actually, the tunability of an inductor can be considerably more than a varactor diode, especially when using a high-permeability ferrite core [4]. The fact that the inductance (permeability) can be tuned is the very advantage in the design of a VCO.…”

“…The theory of tunable inductor was introduced clearly by Jensen [4]. If a ferrite material is placed in a magnetic field of intensity , the magnetic flux density inside the material relates to by the permeability of the material, and approaches a limit when increases.…”

Estimating the Dynamic Response of a Voltage Controlled Oscillator based on Large-Signal Network Analyser Measurements

“…The number of references to related work in the open litterature appears to be low, and when measurements can be found, the description of the measurement procedure is often very limited ( [2], [3]). …”