Feed horn

About: Feed horn is a research topic. Over the lifetime, 2395 publications have been published within this topic receiving 26548 citations. The topic is also known as: feedhorn.

Engineering approach to the design of tapered dielectric-rod and horn antennas

Abstract: The taper profile of optimized dielectric-rod and horn antennas is synthesized as a series of non-interacting planar radiating apertures. The method is semi-empirical, straightforward to apply, enables the dielectric-rod antenna to be satisfactorily optimized and provides a means of evaluating and optimizing a dielectric-horn antenna with variable wall thickness. The optimum profiles are taken as those which smoothly transform the surface-wave power from the launcher to the radiating aperture. The optimization of the dielectric-rod antenna considerably improves the radiation pattern while computations supported by measurements confirm earlier reports that a dielectric-horn can have a higher gain than a metal horn of similar dimension but side-lobe level is seen to be an important issue. Wide flare-angle horns give ideal E-plane patterns at the expense of a high side-lobe level in the H-plane; for small flare angles the dielectric horn gives similar patterns to the tapered rod antenna and thus preserves rotational symmetry. Calculations throughout are restricted to cylindrical geometry but other geometries and variations on the dielectric-horn principles are described. Useful engineering design data have been compiled for both the dielectric-horn and rod antennas and curves are given which determine near-optimum parameters for gains up to about 20 dB which is seen to be a practical operating limit for these surface wave devices. A unified impression of dielectric antennas emerges with the important conclusion that, when optimized, dielectric-rod and horn antennas are in fact competitive with small metal horns for some applications; furthermore the dielectric-horn antenna, used singly or in arrays, is an ideal device for producing a low side-lobe level in the E-plane.

Optimum feeds for all three modes of a monopulse antenna II: Practice

Abstract: In an amplitude-monopulse antenna whose main aperture is illuminated by a feed, it is desired to control the feed excitation independently in the sum, azimuth difference, and elevation difference modes. It is possible to describe a feed system, comprising an infinite array of radiators and hybrid junctions, which demonstrates the principle of complete independent control of the three modes. There are several practical feeds which approach a hypothetical ideal one in varying degrees. One representative type is the "twelve-horn feed;" although it has some disadvantages, it is versatile and quite useful. However the most attractive type for many applications appears to be one having a combination of multiple-horn excitation in one plane and multimode-waveguide excitation in the other. With a simple form of the "multihorn-multimode" feed, the ideal is substantially realized, and a major improvement in monopulse performance can be obtained.

System for short-range transmission of signals over the air using a high frequency carrier

Abstract: A system is provided which transmits either analog or digital data signals over the air. The system includes including a transmitter and a receiver. The transmitter and receiver are arranged to transmit signals using a carrier signal having a high frequency such as in the range of 902-928 MHz. The transmitter and receiver are configured to provide for the transmission of two channels of stereophonic signals while maintaining high signal-to-noise ratios, good frequency response, and low distortion. To provide for the proper transmission of signals between transmitter 10 and receiver 12, these devices include oscillating circuits having ceramic resonators which provide a base frequency which is readily modulated to facilitate proper transmission of either analog or digital signals between the transmitter and receiver. To further improve the transmission capability between the transmitter and receiver, the transmitter and receiver both include substantial buffering, isolation and shielding between selected circuit components to prevent unwanted areas of frequency modulation within the transmitter and receiver.

C-Band Multiple Beam Antennas for Communication Satellites

Abstract: Nowadays, broadband satellites operating at Ka-band and providing high capacity (above 100 Mbps) are mostly based on single-feed-per-beam (SFB) antenna configurations. This antenna farm, using typically three or four reflectors to produce the full dual-band (Tx/Rx) multiple beam coverage, provides high performance but leaves no or little room on the spacecraft for other missions. Accommodation constraints and the desire of operators to maximize and diversify their revenues per satellite have led to several studies on innovative antenna solutions enabling to reduce the number of reflector apertures. Multiple-feed-per-beam (MFB) antenna configurations, using only two apertures, are currently under development for broadband missions at Ka-band. C-band is a more mature business and operators are contemplating the possibility to apply the benefits of multiple beam antennas (MBA) to this frequency band. Due to the lower operating frequency, accommodation constraints are even more stringent and although still scarcely discussed, MFB antenna configurations at C-band are clearly of interest. This paper presents investigations on this topic. In particular, it is found that the MFB architecture applied in C-band is a more realistic approach when compared to the SFB option. Beam Forming Networks (BFNs) with periodic structure is the key to get compact feed clusters that can be allocated in large and medium-size platforms. A new four color scheme compatible with a very compact MFB feed array architecture is introduced.

Cross-polarized parabolic antenna

Abstract: A cross-polarized parabolic antenna employs a horn fed by two rectangular waveguides having their longer transverse dimension in a common plane, with a 90 DEG polarization rotator in the feed between the connection points of the waveguide.