U.S. Philips Corporation

Burkhard Schiek

Jurgen Kohler

Wolfram Schilz

Frans Christiaan De Ronde

Rolf Jacobson

Kai M Ludeke

Range-dependent sensitivity of an RF doppler radar apparatus is reduced to prevent false alarms when small objects move in close proximity to the apparatus' antenna. The sensitivity is reduced by periodically FM-modulating the transmitted RF signal at a frequency corresponding to a wavelength which is at least four times the operating range of the apparatus. The reflection of the transmitted signal is mixed with the transmitted signal to produce a difference frequency signal which is sampled at instants of maximum amplitude.

Doppler radar measuring apparatus

Disclosed is a microwave range measuring system for determing the distance to an object by means of the phase difference between a transmitted frequency-modulated wave and the wave reflected by and received from the object. The frequency of the transmitted microwave signal is varied between two fixed frequencies f.sub.u and f.sub.o and the signal reflected by and received from the object is converted by means of a signal converter into an intermediate frequency signal from whose total phase shift the distance is derived.

Microwave range measuring system for measuring the distance of an object

A method for measuring the physical temperature of objects by means of microwaves using a Dicke radiometer. A noise signal is continuously applied to an antenna which is directed towards the object and is periodically and alternately applied, together with the antenna signal, which includes reflected noise and object emission to the radiometer. The integrated output signal of the radiometer controls the noise power and is proportional to the object temperature.

Method and arrangement for measuring the physical temperature of an

Disclosed is a 180.degree. phase shifter having meander-shaped coupled lines in a predominantly planar form, such as, for example, microstrip, microslot or stripline, formed by a .lambda./2 long meander disposed opposite to a .lambda./4 long meander.

Broad-band 180.degree. phase shifter

A phase shifter having, on one surface of a substrate, a microstrip stub which is connected in parallel to a microstrip line and which is open at one end. Disposed below the stub is a slot which is short-circuited at a point below the open end of the stub, and which ends in an open circuit at the opposite end.

Micro-slot-stripline phase shifter

Planar transducer for microwaves from a micro-strip line to a slotted line, in which a microwave strip line junction in the form of a 'Y' is disposed on the upper side of a substrate, one of the strip line branches being short-circuited, the other one being open, and that a slotted line in the form of a Y, which is in the opposite direction of the first Y, is disposed at the bottom side of the substrate, one slotted line branch being open, the other being short-circuited, whereas the centers of the 'Y'-structures coincide exactly.

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Halstenbek, Germany

Burkhard Schiek