Technique for suppressing spurious resonances in strip transmission line circuits
AssigneeBell Telephone Laboratories, Incorporated
InventorsEric R. Carlson, Martin V. Schneider, Ralph F. Trambarulo
Life of this patent
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Abstract
The present invention relates to a technique for displacing spurious resonances which are excited in strip transmission line circuits outside the frequency band of interest. Such displacement is accomplished by adding apertures in the capacitive elements of the strip transmission line circuit which have dimensions to move the transverse resonances out of frequency band of interest while causing, for example, no significant change in the passband ripple or the stopband attenuation of a filter. The slots effectively cause the inductance across the capacitive element to increase and, therefore, lower the frequency of the transverse modes or resonances.
Claims7
A strip transmission line circuit comprising a layer of an electrically conductive material which is deposited on a dielectric substrate (10), the layer being fabricated into a predetermined pattern of various width sections along a longitudinal axis (20) thereof to form various circuit elements which includes a wide section that forms a capacitive element (13, 15, 17 or 19)
- CHARACTERIZED IN THAT
- the wide section forming the capacitive element comprises an aperture (40, 41, 42 or 43) having dimensions which cause transverse resonances that may be excited in the strip transmission line circuit to be displaced outside a desired frequency band of interest.
A method of displacing transverse modes which are excited in a strip transmission line circuit in a frequency band of interest outside said frequency band where the strip transmission line circuit comprises a layer of an electrically conductive material which is fabricated into a predetermined pattern of various width sections along a longitudinal axis (20) thereof to form various circuit elements of a network which includes a wide section forming a portion of a capacitive elements (13, 15, 17 or 19)
- CHARACTERIZED IN THAT
- the method comprises the step of:
- (a) forming an aperture (41, 42, 43 or 44) in the wide section of the predetermined pattern forming the capacitive element of the network, the aperture having dimensions which cause the transverse modes to be displaced outside the frequency band of interest.
Dependencies are inferred from the claim text.