Abstract: A measurement device comprises a high permittivity dielectric resonator (10) with a low microwave loss tangent and having at least a first symmetry axis (z-i); an electrically conductive resonance chamber (100) containing and geometrically similar to the resonator (10) and having a second symmetry axis (z2) coincident with the first symmetry axis (z-i); the resonance chamber (100) having a plurality of similar ports (104) orthogonal to the first symmetry axis (z-i), each such port (104) having a microwave antenna (114), either to inject microwaves into the resonance chamber, thereby to excite an electric field in the resonator, or to receive microwaves from the resonance chamber; and a comparator circuit (200, 300, 400, 500, 600, 700, 800) connected to a first one (P1) of the plurality of ports (104) to inject microwaves into the resonance chamber and to another (P2, P3) of the plurality of ports (104) to receive microwaves from the resonance chamber; wherein the measurement device further comprises an electr

Abstract: A measurement device comprises a high permittivity dielectric resonator (10) with a low microwave loss tangent and having at least a first symmetry axis (z-i); an electrically conductive resonance chamber (100) containing and geometrically similar to the resonator (10) and having a second symmetry axis (z2) coincident with the first symmetry axis (z-i); the resonance chamber (100) having a plurality of similar ports (104) orthogonal to the first symmetry axis (z-i), each such port (104) having a microwave antenna (114), either to inject microwaves into the resonance chamber, thereby to excite an electric field in the resonator, or to receive microwaves from the resonance chamber; and a comparator circuit (200, 300, 400, 500, 600, 700, 800) connected to a first one (P1) of the plurality of ports (104) to inject microwaves into the resonance chamber and to another (P2, P3) of the plurality of ports (104) to receive microwaves from the resonance chamber; wherein the measurement device further comprises an electr

Abstract: An NMR level gauging device comprising two sets of coils (2, 3) would ortonal to one another about a tank (1). Each set is spaced apart about the tank (1) so as to be capable of providing a substantially uniform magnetic field through the tank when an electric current passes through them. A steady dc current being supplied to coils (2) from a supply (4) and an oscillating electromagnetic field at one or more fixed frequencies is supplied to coils (3) from supply (5); the sets of coils (2, 3) together providing for a substantially position independent sampling of a substance of interest i.eg. fuel, within the tank (1). Detection means (6, 7) are provided for detecting the amplitude of an induced resonance signal in the substance of interest and to provide an amplitude dependent output as a gauge of the amount of substance in the tank (1).

Abstract: A method of determining a response characteristic of a microwave device includes coupling a microwave resonator to the device, loading the resonator with microwave radiation, monitoring the time decay of power from the resonator, and comparing the monitored time decay with a known characteristic of the time decay of radiation in the microwave resonator when loaded with radiation.