Ka band monopulse array antenna with low sidelobe levels
AssigneeViettel Group
InventorsNHU THAI LE, HOAI SON NGUYEN, THI HANG LE
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Abstract
A Ka band monopulse antenna system with a compact size (diameter: 160 mm; height: 25 mm). The monopulse antenna system consists of a monopulse comparator; an unequal power divider and an array of 448 radiating slot antenna elements. The research results of the invention are as follows: the antenna operates in the Ka band frequency range; the realized gain at the center frequency is 34.2 dBi; the sidelobe level of the sum beam on the two E and H planes is less than −25 dB; the difference between the two peaks of the beams on the difference beam is small (about 0.1 dB); the peak-null difference of the difference beam is greater than 43 dB.
Claims5
A Ka-band monopulse antenna system with low side-lobe level including:
- a monopulse comparator;
- an unequal power divider and a slot antenna element array having four component subarrays;
- in which:
- the monopulse comparator has two-channels and uses four T-magics on E and H planes with impedance matching and a WR28 standard waveguide;
- the four T-magics are combined on the E and H planes resulting in a total of eight signal ports:
- four input signal ports connected to the four component antenna subarrays of the slot antenna array;
- one sum port (a sum of four signals from the four component antenna subarrays);
- three difference ports (a difference of the sum of each of two component antenna subarrays on the E, H and 45-degree diagonal planes);
- a Taylor distributed unequal power divider with a structure suitable for a circular profile antenna element array consisting of four stages;
- wherein to limit layout space, the power divider uses a rectangular waveguide;
- in which:
- a first stage of the unequal power divider consists of four identical power splitters with one input port and three output ports using T-junctions on the H-plane with baffles for desired power adjustment and windows for impedance matching;
- the input ports of the three-port power divider on the first stage additionally use waveguide converters;
- a second stage of the unequal power divider uses T-junctions on the H-plane similar to the first stage, wherein the number of splits is greater than the first stage, thereby obtaining 112 output ports on the second stage of the power divider;
- a third stage of the unequal power divider includes 112 radiation slots used to connect the second stage and a fourth stage of the power divider;
- the fourth stage of the unequal power divider consists of 112 sets of four-division resonant cavities;
- wherein the signal after being radiated from the second stage through the radiation slots on the third stage will be divided into four at the four-division resonant cavity;
- the slot antenna element array consists of 448 radiating slot antenna elements arranged in a circular profile corresponding to output ports of the four-division resonant cavities;
- a 2×2 element antenna array is located in the antenna system;
- the 2×2 element antenna array is structured from the second stage of the unequal power divider to a 2×2 element radiating element array.
Dependencies are inferred from the claim text.