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Tunable Coax Bandpass Filters
Tunable Bandpass Waveguide Filters
Tunable Diplexers
Fixed Diplexers
Fixed Triplexers
Fixed Quadriplexers
Fixed Coax Bandpass Filters
Fixed Waveguide Bandpass Filters
Dual Bandpass Filters
Weather Radar Components
Weather Radar Assemblies
Satellite Earth Station Assemblies
Power Combiners
Low Pass Filters
Band Reject Filters
Harmonic Filters
High Power Filters
Programmable Filters
AutoTracking Filters
37-40 GHz Filters
Waveguides & W/G Componets

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Filter Type & Order

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CMC Filters are available in bandpass, lowpass, band reject and highpass designs. When specifying your filter needs, be sure to supply all pertinent information. To achieve the best results, additional specifications such as phase, group delay, power, size, and mechanical requirements should be supplied. Many styles of CMC filters are available in tunable as well as fixed tuned versions. The engineering staff at CMC will be happy to advise you in filter styles to best meet your specific combination of bandwidth, loss, selectivity, size, power handling etc.


Waveguide filters consist of half wavelength resonant cavities coupled by capacitive or inductive irises. Low percentage bandwidths are best realized in cylindrical resonators. Very high Q factors and tuneability are attractive features of this style. Rectangular resonators are better suited to wider percentage bandwidths and offer high Q, very high selectivity, and lower cost.


Coax units consist of quarter wavelength resonant stubs coupled by capacitive or inductive irises. Typical bandwidths range between 0.5 and 2.0%. This style resonator lends itself well to broad tuning ranges or is very economical in fixed versions. Q factors are relatively high and selectivity associated with up to 8 sections is available in tunable versions.


Combline design utilizes distributed inductances and lumped capacitances. Bandwidths up to 30% are realizable. Q factors are relatively high and can be traded against very small package sizes.


Interdigital design distributes both inductances and capacitances in an array of short circuit quarter wavelength lines. Bandwidths up to 100% can be obtained. Q factors are high and can be traded against smaller package sizes.

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To determine the number of resonant sections which are necessary to meet your particular specifications, simply divide the 3db bw into the bandwidth required to meet the rejection characteristics.

Example 3 db bw = 15 MHz
60 db bw = 90 MHz
Ordinate: 60  db bw/3db bw = 90/15 = 6
Abscissa = 60 db which indicates that a 4 section filter is necessary to meet these requirements.
Specifying Filters
Filter Type & Order
Calibration Options
Engineering Assistance



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Coleman Microwave Company P.O. Box 247 Edinburg, VA 22824   1-800-563-3449   1-540-984-8848