Force or vibration indicating device utilizing microwave resonance ferramic gyrators

A very sensitive force or vibration indicating device is claimed and made by the use of the movement of a ferramic rod or slab of a microwave resonance ferramic gyrator in operation with microwave energy. The movement of the ferramic rod or slab is mechanically connected to a force or vibration source. The varied detected output of microwave energy produced by a phase shift caused by the gyrator is detected as a very sensitive indication of force or vibration applied.

BACKGROUND OF INVENTION 
This invention relates to a force or vibration indicating device made by 
the movement of a ferramic rod or slab in a microwave waveguide ferramic 
gyrator operating in a microwave waveguide bridge. The microwave bridge 
electrical balance is altered by the movement inward or outward of a free 
moving ferramic rod or slab in a waveguide gyrator in one arm of the 
bridge. The movement of the rod or slab is by a small dielectric rod 
connected to both the applied force or vibration to be measured and to the 
ferramic rod or slab inside the gyrator thru the waveguide wall. The 
movement controls the microwave electrical phase shift of the gyrator and 
in turn, this microwave power after passing thru the gyrator connected in 
one arm of the microwave bridge thru magic tee's (hybrid junctions) is 
compared to a fixed phase shift in the other bridge arm and is detected. 
The recalibrated and detected bridge unbalance is a direct measure of the 
force or vibration to be measured. 
SUMMARY OF THE INVENTION 
According to the present invention optimum force or vibration measurement 
is obtained with the use of microwave resonance ferramic gyrator slab 
movements relative to the applied force to move the ferrite slab in the 
gyrator in combination with the components described in the operation of 
the invention. Since a small movement of the ferramic rod or slab produces 
a magnitude change in the phase shift of the gyrator in microwave energy 
which is not possible with ordinary probes or dielectric phase shifters. 
Advantageously, the movement of the force sensing components are free in 
air and do not depend on any physical contact to any part of the microwave 
measuring system other than the small dielectric rod or ferrite slab in 
order to transmit movement caused by the force applied to be measured. No 
balancing magnetic fields are needed and any variation of the input 
microwave power can be zeroed on the detector before using. Further, 
present scales or force and vibration devices using a light beam for 
detection of forces applied have only a ruler deflection and do not have 
the advantage of a simple continuous detector dial reading. Further, it is 
difficult to remote a light scale or force defecting systems thru light 
beams. In the present invention this is easily done by extending the 
lengths of the waveguide or by cables to remote positions of the force 
measuring device from the recording position, or by means of microwave 
links the force or vibration devices can be remotely located and 
conventiently read at a central position. The microwave detector output 
can also be easily converted to a digital signal by the addition of an A/D 
converter for the microwave detector output.

It is to be understood that the foregoing description and accompanying 
drawings relates to embodiments set out by way of illustration not by way 
of limitation. Numerous other embodiments and variations are possible with 
the spirit and scope of the invention--its scope being defined by the 
appended claims. 
DESCRIPTION OF INVENTION 
The invention as applied to a force measurement system consisting of a beam 
balance scale with accompanying adjustable tare weight now will be 
described by way of example and reference to the accompanying drawings. 
FIG. 1 consists of a microwave source (1) connected thru a waveguide 
isolator (2) and directional coupler (3) connected to a magic tee (4) 
(hybrid junction) waveguide configuration where the power is split between 
the two rectangular legs (5) and (6). One leg contains a gyrator as shown 
in FIG. 2 and 2a; the other leg causes a fixed phase shift and contains 
another magic tee (7). 
It is known that a gyrator in microwave use produces zero phase shift for 
one direction of propagation and a 180.degree. phase shift for the other 
direction. Thus for one direction of propagation signals from (5) and (6) 
arms of the hybrid (4) arrive at hybrid (6) in phase since the electrical 
lengths of both propagation paths A and B are set to the same electrical 
length while signals from hybrid (6) caused by the waveguide short (7) in 
the reverse direction arrive at the input out of phase caused by the 
reverse 180.degree. phase shift of the gyrator and are so transmitted by 
the E plane arm of hybrid (4) containing the crystal detector (8). In this 
way complete transmission occurs between (1) to (7) to (8). With the 
application of the gyrator (10) as shown in FIGS. 2 & 2a the phase shift 
between (7) and (8) via (10) is altered by the movement of the ferrite rod 
or slab and propagation is not complete to the crystal detector at (8). 
The microwave power at crystal detector (8) is reduced and the power at 
crystal detector (9) is increased by the change of the reverse phase shift 
in the gyrator caused by force applied to move the ferramic rod or slab in 
the gyrator interior by a dielectric rod connected to the slab or rod thru 
a small clearance hole to the interior of the gyrator as shown in FIGS. 2 
and 2a. The invention is now clearly apparent that with an electrical 
short placed at port (7) and a gyrator (10) with a movable ferramic slab 
or rod connected by dielectric rods thru clearance holes in the waveguide 
gyrator to the external force applied replacing a fixed 180.degree. phase 
shift gyrator, the output voltage of crystal detectors (8) and (9) will be 
varied according to the movement of the ferrite slab in the gyrator (10). 
The detected output of crystal (8) compared to the reflected power 
returning thru crystal (9) is a very sensitive indication of the force 
applied thru the dielectric rods to the gyrator (10). The ratio of power 
after calibration in crystal (8) compared to the power reflected into 
crystal (9) when directed thru a meter (11), thru an amplifier (12) thru 
A/D converter (13) and to display (14) is a direct measure of force or 
vibration applied to the dielectric rod in the gyrator. 
FIG. 2 and 2a shows the gyrator (10) with an accompanying permanent bias 
magnet and the movable ferramic rod or slab within the waveguide. A small 
dielectric rod (16) is cemented to the movable ferramic rod or slab (17) 
and connected to pivot or fixed and cemented to the exterior weight, force 
or vibration applied (20) thru a small clearance hole (18) in the side of 
the waveguide (19). Initial setting of the ferramic rod or slab is for a 
position of 180.degree. microwave phase shift thru the gyrator. Any 
deviation from this position of the ferramic rod or slab in the presence 
of the gyrator permanent magnetic bias field caused by force or vibration 
applied thru the dielectric rod increases or decreases the phase shift 
thru the gyrator and unbalances the microwave bridge arrangement as shown 
in FIG. 1 and described in the operation of the invention. 
A further embodiment of the invention shown in FIG. 1 is where the force 
applied to move the ferramic rod or slab in the gyrator is applied thru 
the dielectric rod connected to a vertical pendulum to measure 
seismographic oscilations.