Abstract A band-pass filter for use in the VHF and UHF regions employs a digital line in which the length of the digits can be as short as one twelfth of the wavelength at the filter''s midband frequency to permit the filter structure to be small compared to the wavelengths in the pass band while obtaining the advantage of the low loss of a digital line. The filter has an elliptic function and is particularly suitable for narrow band applications. The digital line is disposed between and spaced from a pair of ground plane plates and the line is formed by parallel digits which are short circuited at one end in the manner of a ''''comb'''' line. At the opposite end is a network of lumped element capacitors interconnecting adjacent digits of the line and coupling the end of each digit to ground.
A band-pass filter comprising a pair of spaced ground planes, a network of spaced parallel digits disposed between the ground planes, the digits of the network having their corresponding ends short circuited to ground and their opposite ends open circuited to form a comb line, a network of lumped capacitors, each digit having its open circuited end coupled to ground by a different capacitor of the network, and each adjacent pair of digits being coupled at their open circuited ends by a different capacitor of the network.
Claim 2
Dependent Claim
87 words
A band-pass filter comprising a pair of spaced ground planes, a network of spaced parallel digits disposed between the ground planes, the digits of the network having their corresponding ends short circuited to ground and their opposite ends open circuited to form a comb line, a network of lumped capacitors, each digit having its open circuited end coupled to ground by a different capacitor of the network, and each adjacent pair of digits being coupled at their open circuited ends by a different capacitor of the network.
Claim 3
Dependent Claim
33 words
The band-pass filter according to claim 1 wherein the digits of the comb line are less than an eighth of a wavelength in circuited compared to the wavelength at the filter''s mid-band frequency.
Claim 4
Dependent Claim
36 words
The band-pass filter according to claim 2 further including an input and an output capacitor, each capacitor being connected to the open circuited end of a different one of the terminal digits in the comb line.