Mitsubishi Denki Kabushiki Kaisha

Other

Takashi Ebisui

Takashi Katagi

Shuji Urasaki

Katsuhiko Aoki

Hiroyuki Deguchi

Tadashi Takano

Koryo Miura

A positioner supports an antenna at an optional rotating angle and the mirror surface of the antenna at different rotating angles is measured. A computer expands the measured value into series using polar coordinates system associated with the measuring system, whereby the intrinsic deformation of the mirror surface under the zero-gravity condition and the deformation due to gravity are separately measured.

Antenna mirror-surface measuring system

A conical horn antenna applicable to plural modes of electromagnetic waves is substantially composed of a feed waveguide positioned on the base end side and feeding a dominant mode of an electromagnetic wave, a conical horn positioned on the fore end side and radiating electromagnetic waves of plural modes including dominant and higher modes, and a desired mode of electromagnetic wave generating portion provided between the feed waveguide and the conical horn and generating an electromagnetic wave of a desired higher mode. The electromagnetic wave generating portion is composed of straight cylindrical waveguides having the same or different inside diameters and having a predetermined relation to the wavelength of maximum frequency and that of minimum frequency in a certain frequency band, and tapered waveguides which connect stages of said straight cylindrical waveguides, a feed waveguide and a conical horn, respectively, through truncated cone-like inner peripheral surfaces thereof and which expand forwardly from the base end side. The tapered waveguide adjacent to the feed waveguide may be constructed of two tapered portions having a gentle expansion angle on the base end side and a sharp expansion angle on the fore end side. n

Conical horn antenna applicable to plural modes of electromagnetic waves

An earth station antenna is employed for telecommunicating with a satellite in combination with an automatic tracking apparatus. The antenna is a dual reflector antenna which comprises a main reflector, a sub-reflector and a primary radiator, and the used frequency band of the antenna is at least 1.8 octaves. A parameter t of the antenna, defined by a configuration of the primary radiator is less than 0.3 at the lowest operating frequency. The phase center of the primary radiator, at a low frequency within the operating frequency range, is made to correspond with the focus of the sub-reflector. The above parameter t is defined by: ##EQU1## where: .lambda.: wavelength in free space,

Dual reflector antenna

Growing community of inventors

Kanagawa, Japan

Takashi Ebisui