Modular narrow-band dipole antennas
A narrow-band dipole antenna module comprising: a housing comprising a base having an opening defined therein, and a hollow post extending from the opening and having a plurality of antenna openings defined therein; a circuit assembly configured for insertion into the housing comprising: an input printed circuit board having transmit and receive connectors thereon; a matching printed circuit board having lumped element matching components and a plurality of terminal blocks thereon; a pair of coaxial feed lines connected between the input and matching printed circuit boards, each having a coil formed therein such that the feed lines act as a balun; and at least one rigid support member connected between the input and matching printed circuit boards such that when the circuit assembly is inserted into the housing the terminal blocks are adjacent the antenna openings; and a plurality of antenna elements configured to be connected to the terminal blocks.
1 . A narrow-band dipole antenna module comprising:
a housing comprising a base plate having an opening defined therein, and a hollow post extending from the opening in the base plate, the hollow post having a plurality of antenna openings defined therein near a distal end thereof;
a circuit assembly configured for insertion into the housing, the circuit assembly comprising: an input printed circuit board having a transmit connector and a receive connector thereon for connecting to an antenna-driving circuit;
a matching printed circuit board having lumped element matching components and a plurality of terminal blocks thereon;
a plurality of antenna elements configured to be received through the antenna openings and connected to the terminal blocks;
wherein each of the terminal blocks is configured to receive an antenna element of the plurality of antenna elements;
a pair of coaxial feed lines connected between the input printed circuit board and the matching printed circuit board, each of the pair of coaxial feed lines having a coil formed therein such that the pair of coaxial feed lines acts as a balun; and
at least one rigid support member connected between the input printed circuit board and the matching printed circuit board to hold the matching printed circuit board at a fixed distance from the input printed circuit board such that when the input printed circuit board is mounted to an underside of the base plate, the terminal blocks on the matching printed circuit board are adjacent the antenna openings in the hollow post and connecting the plurality of antenna elements to the plurality of terminal blocks.
2 . The narrow-band dipole antenna module of claim 1 wherein one of the pair of coaxial feed lines has a clockwise coil formed therein and the other of the pair of coaxial feed lines has a counterclockwise coil formed therein.
3 . The narrow-band dipole antenna module of claim 1 , wherein the matching printed circuit board has a first face facing the input printed circuit board and a second face opposite the first face with the terminal blocks mounted on the second face, and comprises a pair of feed line landing pads for connecting to the pair of coaxial feed lines, each feed line landing pad comprising an annular ring on the first face of the matching printed circuit board for connecting to an outer conductor of one of the coaxial feed lines, and a plated through hole extending from within to the annular ring on the first face to the second face of the matching printed circuit board for connecting to an inner conductor of the feed line.
4 . The narrow-band dipole antenna module of claim 1 further comprising an isolator element for each of the plurality of antenna openings, the isolator element having a protrusion extending from a first side thereof configured to engage one of the antenna openings, and a recess on a second side thereof for receiving one of the antenna elements of the plurality of antenna elements, the recess having an aperture therein extending to the first side of the isolator element to permit said one of the antenna elements of the plurality of antenna elements to directly engage a terminal block of the terminal blocks.
5 . The narrow-band dipole antenna module of claim 4 further comprising a first sealing ring between the first side of the isolator element and the housing for forming a seal between the isolator element and the housing, and a second sealing ring between the second side of the isolator element and said one of antenna elements for forming a seal between the isolator element and said one of antenna elements of the plurality of antenna elements.
6 . The narrow-band dipole antenna module of claim 1 , wherein the terminal blocks are configured to hold each antenna element of the plurality of antenna elements at an angle of 45 degrees from a longitudinal axis of the hollow post.
7 . The narrow-band dipole antenna module of claim 6 , wherein the plurality of antenna openings comprises four antenna openings, the plurality of terminal blocks comprises four terminal blocks, and the plurality of antenna elements comprises four antenna elements.
8 . The narrow-band dipole antenna module of claim 1 , wherein the hollow post is configured to be adjustable in height.
9 . The narrow-band dipole antenna module of claim 1 , wherein the plurality of antenna elements are configured to be adjustable in length.
10 . A method for assembling a narrow-band dipole antenna, the method comprising:
assembling a circuit assembly comprising an input printed circuit board having a transmit connector and a receive connector thereon for connecting to an antenna-driving circuit, a matching printed circuit board having lumped element matching components and a plurality of terminal blocks thereon, each of the terminal blocks is configured to receive an antenna element of a plurality of antenna elements, a pair of coaxial feed lines connected between the input printed circuit board and the matching printed circuit board, each of the pair of coaxial feed lines having coil formed therein such that pair of coaxial feed lines acts as a balun, and at least one rigid support member connected between the input printed circuit board and the matching printed circuit board to hold the matching printed circuit board at a fixed distance from the input printed circuit board;
inserting the circuit assembly into a housing comprising a base plate having an opening defined therein and a hollow post extending from the opening in the base plate, the hollow post having a plurality of antenna openings defined therein near a distal end thereof such that when the input printed circuit board is mounted to an underside of the base plate, the terminal blocks on matching printed circuit board are adjacent the antenna openings in the hollow post; and
connecting the plurality of antenna elements to the plurality of terminal blocks.
11 . The method of claim 10 , wherein one of the pair of coaxial feed lines has a clockwise coil formed therein and the other of the pair of coaxial feed lines has a counterclockwise coil formed therein.
12 . The method of claim 10 , wherein the matching printed circuit board has a first face facing the input printed circuit board and a second face opposite the first face with the terminal blocks mounted on the second face, and comprises a pair of feed line landing pads for connecting to the pair of coaxial feed lines, each feed line landing pad comprising an annular ring on the first face of the matching printed circuit board for connecting to an outer conductor of one of the coaxial feed lines, and a plated through hole extending from within to an annular ring on the first face to the second face of the matching printed circuit board for connecting to an inner conductor of said one of the coaxial feed lines.
13 . The method of claim 10 , wherein connecting the plurality of antenna elements further comprises connecting an isolator element for each of the plurality of antenna openings, the isolator element having a protrusion extending from a first side thereof configured to engage one of the antenna openings, and a recess on a second side thereof for receiving one of the antenna elements of the plurality of antenna elements, the recess having an aperture therein extending to the first side of the isolator element to permit said one of the antenna elements of the plurality of antenna elements to directly engage a terminal block of the terminal blocks.
14 . The method of claim 13 , wherein connecting the plurality of antenna elements further comprises connecting a first sealing ring between the first side of the isolator element and the housing for forming a seal between the isolator element and the housing, and a second sealing ring between the second side of the isolator element and said one of the antenna elements of the plurality of antenna elements for forming a seal between the isolator element and said antenna element of the plurality of antenna elements.
15 . The method of claim 10 , wherein the terminal blocks are configured to hold the antenna elements at an angle of 45 degrees from a longitudinal axis of the hollow post.
16 . The method of claim 10 , wherein the plurality of antenna openings comprises four antenna openings, the plurality of terminal blocks comprises four terminal blocks, and the plurality of antenna elements comprises four antenna elements.
17 . A system comprising:
a housing comprising a base plate having an opening defined therein, and a hollow post extending from the opening in the base plate, the hollow post having a plurality of antenna openings defined therein near a distal end thereof, wherein a height of the hollow post is configured to be adjusted;
a circuit assembly configured for insertion into the housing, the circuit assembly comprising:
an input printed circuit board having a transmit connector and a receive connector thereon for connecting to an antenna-driving circuit;
a matching printed circuit board having lumped element matching components and a plurality of terminal blocks thereon;
a plurality of antenna elements configured to be received through the antenna openings and connected to the terminal blocks;
wherein each of the terminal blocks is configured to receive an antenna element of the plurality of antenna elements;
a pair of coaxial feed lines connected between the input printed circuit board and the matching printed circuit board; and
at least one rigid support member connected between the input printed circuit board and the matching printed circuit board to hold the matching printed circuit board at a fixed distance from the input printed circuit board such that when the input printed circuit board is mounted to an underside of the base plate, the terminal blocks on the matching printed circuit board are adjacent the antenna openings in the hollow post; and
wherein lengths of the antenna elements of the plurality of antenna elements are configured to be adjusted.
18 . The system of claim 17 , wherein each of the pair of coaxial feed lines having a coil formed therein such that the pair of coaxial feed lines acts as a balun.
19 . The system of claim 18 , wherein one of the pair of coaxial feed lines has a clockwise coil formed therein and the other of the pair of coaxial feed lines has a counterclockwise coil formed therein.
20 . The system of claim 17 , wherein the plurality of antenna openings comprises four antenna openings, the plurality of terminal blocks comprises four terminal blocks, and the plurality of antenna elements comprises four antenna elements.