Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
131 words
A filter circuit tunable to microwave frequencies, the circuitry comprising two successive transverse branches, each of which includes, connected in series, a first inductance (LI; L2), which is fixed; a second inductance (L4; L5), which is adjustable; a capacitance diode (Dl; D2); and a high-frequency by-pass, both ends of the series circuit being connected to ground, in which case the capacitance of the capacitance diode (Dl; D2) is controlled by means of a DC signal (S) and the input of the circuit is between the fixed inductance (L1) and the adjustable inductance (L4) of the first transverse branch and its output respectively at the corresponding point on the second transverse branch (L2; L5), characterized in that the high-frequency by-pass is made up of a series resonance circuit (D3, L6; D4, L7).
Claim 2
Dependent Claim
131 words
A filter circuit tunable to microwave frequencies, the circuitry comprising two successive transverse branches, each of which includes, connected in series, a first inductance (LI; L2), which is fixed; a second inductance (L4; L5), which is adjustable; a capacitance diode (Dl; D2); and a high-frequency by-pass, both ends of the series circuit being connected to ground, in which case the capacitance of the capacitance diode (Dl; D2) is controlled by means of a DC signal (S) and the input of the circuit is between the fixed inductance (L1) and the adjustable inductance (L4) of the first transverse branch and its output respectively at the corresponding point on the second transverse branch (L2; L5), characterized in that the high-frequency by-pass is made up of a series resonance circuit (D3, L6; D4, L7).
Claim 3
Dependent Claim
49 words
A filter circuitry according to claim 1, characterized in that the resonance frequency of the series resonance circuit (D3, L6; D4, L7) is essentially the same as the resonance frequency of the two first inductances (L1, L4; L2, L5) and the capacitance diode (Dl; D2) of the transverse branch.
Claim 4
Dependent Claim
31 words
A filter circuit according to claim 1 or 2, characterized in that the series resonance circuit is made up of a capacitance diode (D3; D4) and an adjustable inductance (L6; L7)
Claim 5
Dependent Claim
40 words
A filter circuit according to any of claims 1 to 3, characterized in that a DC signal is connected to a point between the capacitance diodes (D1, D3; D2, D4) on each transverse branch via a series resistor (R1; R2).
Claim 6
Dependent Claim
125 words
A filter circuit according to claim 3 or 4, characterized in that it is implemented on a two-sided circuit card in such a way that the substantially uninterrupted lower-side foil of the circuit card constitutes the ground level, that on the top side there are placed the two capacitance diodes (Dl, D3; D2, D4) of each transverse branch in series, and at a point between them there is connected a series resistor (Rl; R2), in which case the lengths of wire remaining on each side of the connection point form part inductances (L4", L6'; L5", L7'), and that a series inductance (L3) of the circuit connected between the input point and the output point is implemented as a strip of foil on the top side.