No abstract

No abstract

The lens antenna is one of favorable types of antenna at millimeter-wave frequencies since it is structurally simple and of small size. This paper presents a design of a high-performance 35GHz monopulse lens antenna with high aperture efficiency and low sidelobes for missile seeker applications. First, a lens is designed based on the antenna requirements. Next, a monopulse feed is designed utilizing tapered dielectric rods. For ease in the implementation of the monopulse comparator network, a 5-element configuration is adopted where the sum-channel element is separated from difference-channel elements. Finally the monopulse feed and the lens are combined to complete the antenna design. The designed antenna with a 16-wavelength diameter aperture has the sum-channel performance of 32.3dBi gain, 4.24° beamwidth,-28.4dB sidelobe level, and the difference-channel performance of 29.0dBi gain, 2.36° cross-over angle,-23.5dB sidelobe level, and null depth of greater than 40dB.

In this paper, an improved design is presented for a Ka-band monopulse feed with five dielectric rods for use in a Cassegrain reflector or lens antenna. This paper presents a design method of a simultaneous optimization of sum and difference patterns by adjusting the rod length and the rod spacing. The proposed method is applied to design an example design of a monopulse feed. Over 10% of the Ka-band center frequency, the designed feed has, in the case of the sum pattern,-10dB beamwidth of 46°~48°, gain of 16.4~17.4dB, cross polarization level-30~-40dB, phase error of 4.3°~21° within-10 dB beamwidth. In the case of the difference pattern, the designed feed has, at the center frequency, gain of 15.2dB, null depth greater than 50dB, and gain taper of 5dB at-10dB beamwidth of the sum pattern. To verify the validity of the design method, a Ka-band monopulse feed is fabricated and its gain patterns are measured and analyzed.

No abstract