filters and cavities - suotimet
DESCRIPTION
Our Coaxial cavity filtersTRANSCRIPT
COAXIAL CAVITIES
Box 22 Tel. +358 9 2790 120 http://www.aerial.fi04401 Järvenpää Fax +358 9 2910 210 [email protected]
DESCRIPTION
Aerial Oy supplies coaxial cavity resonators for filterapplications. Different kinds of cavity circuitcombinations can be constructed to reject interferingfrequencies or to isolate receivers or transmitterswhen using a common antenna.
Power rating, transmission and VSWR valuesdepend on the selected cavity combination, filteredfrequencies, interconnection cable and connectortypes which are all agreed with the customer. Tuningis factory-made at Aerial Oy premises unless agreedotherwise.
COAXIAL CAVITIES
MECHANICAL AND ELECTRICAL DATA
Type CR110-75 CR110-95 CR200-95 CR110-120 CR110-150 CR110-450
Tuning range 68-88 MHz 88-108 MHz 88-108 MHz 118-144 MHz 146-174 MHz 380-470 MHz
RF-connector N female N female 7/16 female N female N female N female
Diameter ∅ 110 mm ∅ 110 mm ∅ 200 mm ∅ 110 mm ∅ 110 mm ∅ 110 mm
FEATURES
§ Available as single cavity or multicoupler§ Passive element à minimum maintenance,
maximum power§ Temperature drift compensated by using Invar
steel as a conductor piston (tuning rod) material.§ Constructed and tuned individually according to
the customer’s order§ Materials: Aluminium alloy and silver plated brass§ Colour: Light grey§ High power version CR200-95 available for FM§ Installation between antenna and receiver(s) or
transmitter(s).
COAXIAL CAVITIES
Box 22 Tel. +358 9 2790 120 http://www.aerial.fi04401 Järvenpää Fax +358 9 2910 210 [email protected]
TRANSMISSION CURVECR150-1, Single cavity
-80
-70
-60
-50
-40
-30
-20
-10
0
-1 0 1 2 3 4 5
f [MHz]
Tra
nsm
issi
on
[dB
]
-0,5 dB -1 dB -2 dB -3 dB
TRANSMISSION CURVECR150-2, Two cavity combination
-80
-70
-60
-50
-40
-30
-20
-10
0
-1 0 1 2 3 4 5
f [MHz]
Tra
nsm
issi
on
[d
B]
-1 dB -2 dB -4 dB -6 dB
TRANSMISISON CURVECR150-3, Three cavity combination
-80
-70
-60
-50
-40
-30
-20
-10
0
-1 0 1 2 3 4 5
f [MHz]
Tra
nsm
issi
on
[dB
]
-1,5 dB -3 dB -6 dB
BANDPASS FILTERS
Shape and steepness of the transmission curvecan be adjusted by selecting the most suitableout of four possible positions of the couplingloops which are situated in the front panel of thecavity (see the picture below). However usingradical coupling affects also the bandpassattenuation so this feature has to be useddeliberately.
Adjustable loops are available for cavities with N-connectors only.
Illustrating example curves of one, two and threecavity circuits with different loop settings are below.
COAXIAL CAVITIES
Box 22 Tel. +358 9 2790 120 http://www.aerial.fi04401 Järvenpää Fax +358 9 2910 210 [email protected]
NOTCH FILTERS
To reject interfering spot frequencies coaxial cavitycircuits can be tuned as notch filters. Some examples ofpossible 146…174 MHz range patterns are below:
TRANSMISSION CURVECR150-1 Notch filter, single cavity
-30
-25
-20
-15
-10
-5
0
-3 -2 -1 0 1 2 3
f [MHz]
Tra
nsm
issi
on
[d
B]
TRANSMISSION CURVECR150-2 Notch filter, Two cavities
-60
-50
-40
-30
-20
-10
0
-3 -2 -1 0 1 2 3
f [MHz]
Tran
smis
sion
[dB
]
TRANSMISSION CURVECR150-1 Notch filter, single cavity
-25
-20
-15
-10
-5
0
-3 -2 -1 0 1 2 3
f [MHz]
Tran
smis
sion
[dB
]
TRANSMISSION CURVECR150-2 Notch filter, Two cavities
-60
-50
-40
-30
-20
-10
0
-3 -2 -1 0 1 2 3f [MHz]
Tra
nsm
issi
on
[dB
]
TRANSMISSION CURVECR150-1 Notch filter, Single cavity
-25
-20
-15
-10
-5
0
-3 -2 -1 0 1 2 3
f [MHz]
Tra
nsm
issi
on
[d
B]
TRANSMISION CURVECR150-2 Notch filter, Two cavities
-60
-50
-40
-30
-20
-10
0
-3 -2 -1 0 1 2 3
f [MHz]
Tran
smis
sion
[dB
]
COAXIAL CAVITIES
Box 22 Tel. +358 9 2790 120 http://www.aerial.fi04401 Järvenpää Fax +358 9 2910 210 [email protected]
Antenna
Input Input
DUPLEXERS (MULTICOUPLERS)
Duplexer circuits can be used to couple multiple receiversor transmitters to a common antenna. This followingmeasured example graph is a FM duplexer whichcouples two local radio transmitter feed signals togetherfor common feed cable and antenna system. The blockdiagram of the system is on the right.
f1 = 105,2 MHzf2 = 107,7 MHzBandpass attenuation 0,6 dBIsolation 45 dB
System return loss can be matched better than 20 dB fora ±100 kHz frequency band.
TRANSMISSION CURVE2 x CR200-95-2 Duplexer
-50
-45
-40
-35
-30
-25
-20
-15
-10
-5
0
104 105 106 107 108 109
f [MHz]
Tra
nsm
issi
on
[d
B]
ORDERING INFORMATION
To order a correct filter type please contact our salespersonnel and be prepared to inform us about thefrequencies, bandwidths, Return loss values, powerhandling, bandpass and band reject attenuation orisolation which are required in your system. You can alsoleave the decision to our skilled engineers.