INPUT COUPLING ADJUSTMENT ARRANGEMENT FOR RADIO FREQUENCY FILTERS

AGENCEMENT DE REGLAGE DE COUPLAGE D'ENTREE POUR DES FILTRES DE FREQUENCE RADIO

English Abstract

An arrangement for adjustably coupling a radio frequency input port to a
resonator element of the filter. The arrangement comprises a resilient
conductor (19)
which extends from the input port (15) into the electric field of a resonator
element (2).
The remote end of the resilient conductor resiliently abuts the point (20) of
an
adjustment screw (20a). Operating the screw moves the resilient conductor in
relation
to the electric field and alters the capacitive coupling between the input
port and the
resonator element for fine tuning the impedance match of the input to the
filter.

Claims

4

The claims defining the invention are as follows:

1. A radio frequency filter comprising a housing means containing at least one
resonator element, an input port means and at least one output port means,
said filter
further including an arrangement for adjustably coupling said input port means
to at
least one resonator element, said arrangement comprising an elongated
resilient
conductor element of a predetermined dimension arranged to capacitively couple
said
input port means to said at least one resonator element's electric field zone,
wherein
said resilient conductor element is arranged to co-operate with lever means of
electrical insulating material that can be manually activated by a connected
actuating
means mounted externally in a wall of said housing means, to move said
resilient
conductive element thereby adjusting capacitive coupling between said input
port
means and said resonator element's electric field.
2. A radio frequency filter as claimed in claim 1, wherein said resilient
conductor
extends from a part of the input port means such that the resilient
conductor's free end
resiliently abuts said lever means.
3. A radio frequency filter as claimed in claim 1 or 2, wherein said actuating
means is a screw whose point forms the said lever means.
4. A radio frequency filter as claimed in any one of the preceding claim,
wherein
said at least one resonator element is a co-axial resonator.
5. A radio frequency filter as claimed in claim 4, comprising a plurality of
the
coaxial resonators.
6. A radio frequency filter comprising a housing means containing a first
array of
coupled resonator elements and an adjoining second array of coupled resonator
elements, an input port means common to both arrays and respective output port
means for each array, said filter further including an arrangement for
adjustably
coupling said input port means to a first resonator element in each array,
said
arrangement comprising an elongated resilient conductor extending from a part
of
said input port means to a first resonator elements' electric field zone, each
end
portion of said resilient conductor resiliently abutting the point of a
respective
adjustment screw of a electrical insulating material mounted in a wall of said
housing
and whose screw heads are outside said housing, whereby co-operation of
respective
screws moves associated end portions of said resilient conductor thereby
adjusting




5

capacitive coupling between said input port means and an associated resonator
elements electric field.
7. A radio frequency filter as claimed in any one of the preceding claims,
wherein
said electrical insulating material is aluminium oxide.

Representative Drawing