Abstract: The invention is a mechanically or electro-mechanically driven phase shifter for radio frequencies. It is a device for phase shifting a signal propagating through a transmission line by moving a conductive construct between an active line and a ground plane of the transmission line. The conductive construct capacitively couples with either the active line and/or the ground plane, forming a capacitive shunt that reflects a significant part of the signal. The remaining portion of the signal is reflected at a terminated end of the transmission line, resulting in substantially no signal loss. The reflectance of the conductive constructs is determined by its capacitance to active line and ground, by its length, and by the step in the field-distribution at the interface between air-suspended and sledge-suspended sections.

Abstract: A radio frequency network analyzer connected to a multi-port test set is calibrated. An initial calibration is performed for each test set port in the multi-port test set. The initial calibration is performed by first performing a measurement calibration using calibration standards. The calibration standards are located in a reference plane located outside the multi-port test set. The measurement calibration yields initial calibration coefficients. Also the initial calibration includes measuring electronic standards within the multi-port test set to produce initial measured electronic standards. The initial calibration coefficients and the measured electronic standards are used to generate initial corrected electronic standards.

Abstract: A microelectro-mechanical device which includes a fixed electrode formed on a substrate, the fixed electrode including a transparent, high resistance layer, and a moveable electrode formed with an anisotropic stress in a predetermined direction and disposed adjacent the fixed electrode. The device includes first and second electrically conductive regions which are isolated from one another by the fixed electrode. The moveable electrode moves to cover the fixed electrode and to electrically couple to the second conductive region, thus electrically coupling the first and second conductive regions, in response to a potential being applied across the fixed and moveable electrodes. The fixed electrode is transparent to electromagnetic signals or waves and the moveable electrode impedes or allows transmission of electromagnetic signals or waves.

Abstract: A rotary coupled transmission line cell is disclosed which generates standard electromagnetic waves needed for measuring the electromagnetic wave susceptibility (EMS), for measuring the electromagnetic wave interference (EMI) and for correcting the probe. In the present invention, two internal conductors are used to have a 4-port structure, and therefore, the generation of the circulation transmission waves are inhibited during the generation of the standard waves having arbitrary impedances. Therefore, accurate standard waves can be generated, and adjustments of arbitrary polarizations and arbitrary irradiating directions are made possible. Further, when an odd mode power supply is carried out to the internal conductors, the standard electromagnetic waves having a uniformity as high as 3 times that of the conventional ones can be generated. Further, an inverted L shaped test object supporting plate is installed, so that the polarization can be carried out with a greater adjustment width.

Abstract: A tuner for radio frequency coaxial cable transmission lines is provided. It requires only one micrometer adjusting screw since the capacitor electrode that mates with the central conductor of the coaxial line is not only curved to give a large area in proximity to the central conductor but is rectangular and much longer than the diameter of the micrometer screw.

Abstract: A desired frequency response of a microwave network on a monolithic microwave integrated circuit (MMIC), a microwave integrated circuit (MIC), or a hybrid circuit is achieved by selectively switching MEM switches to change the network topology. In a filter network, MEM switches connected between capacitors and inductors are selectively switched to change the network configuration to achieve a desired frequency response. In an amplifier network, the MEM switches are selectively switched to tune the amplifier to a desired frequency response and to reduce harmonic output.

Abstract: A variable differential phase shifter is provided. The device provides a continuous variation in phase between two outputs derived from a single input. The device is suitable for application at signal frequencies around 900 MHz, and is constructed in the form of an inner (38) and outer (37) sleeve capacitively coupled to an inner conductive rod (24) and outer conductive tube (26) respectively, wherein the inner (38), and outer (37) sleeves are connected to an input and can be moved in fixed relative relation thereby varying the phase relationship between the two outputs which are connected to the inner rod (24) and outer tube (26). A dielectric layer (25 and 27) may be provided around the inner rod (24) and outer tube (26). An unequal power division version of the device is provided for by the inclusion of a dielectric tube surrounding a portion of the inner rod.

Abstract: A matching arrangement matches and turns the impedance of a high frequency surface acoustic wave (SAW) filter (3) to the characteristic impedance of an external system. The arrangement includes a power divider/combiner (9,10) with 180 degrees phase difference between the two output ports of the divider--or input ports of the combiner--and an adjustable capacitor (15, 24) installed between the power divider/combiner (9,10) and the SAW-filter (3). The arrangement may be a microstrip network where the power divider/combiner includes a Wilkinson-divider (9,10) in combination with a 180 degrees phase-shift (11,12) between the output arms (13, 14; 20, 21) of the divider (9,10).

Abstract: A summing network for combining and feeding radio frequency signals supplied by radio transmitters to common antenna means, includes conductors, connectors and a stub. In order to make the tuning of the summing network easier, the stub includes a changer for changing the electrical length of the summing network as a response to a control signal fed to the stub.

Abstract: An impedance converting device comprises a tri-plate structure having a first grounded conductor member (21) a second grounded conductor member (22) located apart from the first grounded conductor member to form a space between the first and the second grounded conductor members, and a line conductor member (23) located in the space for allowing a signal to pass therethrough. The impedance converting device comprises a varying section (31 to 37) for varying a terminative condition of the electric flux generated from the line conductor member. The varying section may be a window section (31 to 34) formed in the second grounded conductor member at a predetermined location. The varying section may include a metal portion (35, 36) and a slave window section (37). The window section is partially covered with the metal portion. The slave window section is connected to the window section.

Abstract: The present invention relates to a for coupling Plain Old Telephone Service (POTS) signals and Asymmetric Digital Subscriber Line (ADSL) signals to a common line (TL). In order to avoid saturation of inductances (L1,L2,L3,L4) of a low pass POTS filter (LPF) located between the POTS transmitter/receiver (PTR) and this common line (TL) when the POTS signal is not sufficiently attenuated by this common line (TL), a variable impedance (SL) is inserted between the POTS transmitter/receiver (PTR) and this low pass POTS filter (LPF). The value of this variable impedance (SL) is controlled by a control signal (CS) supplied by the ADSL transmitter/receiver (ATR) which measures the attenuation caused by this common line (TL).

Abstract: An input transformer for a coaxial transmission line is provided which allows continuously variable amplitude and phase of an RF signal conducted on the transmission line. The transformer comprises a housing having a longitudinal axis. A center conductor of the coaxial line extends along the axis through the housing. A first sleeve is axially movable within the housing, and has contact points on an outer surface thereof to provide electrical conductivity between the first sleeve and the housing. The ability of the first sleeve to move axially enables variability in the location of the transformer along the transmission line. The first sleeve has an inner wall that is eccentric relative to the longitudinal axis of the center conductor. A second sleeve having a cylindrical outer wall is disposed within the first sleeve. The second sleeve is rotationally movable within the first sleeve, and has contact points on the outer wall to provide electrical conductivity between the first sleeve and second sleeve.

Abstract: Disclosed are electronic elements with variable electrical characteristics, each element including at least one microcavity in which there shifts, with a limited clearance or range of play, at least one moving element made of an insulator material that is at least partially covered with electrically conductive material, and that works together with at least one microwave circuit of the substrate, and means creating an electrical field to shift the moving element.

Abstract: A magnetostatic wave microwave device comprising a thin magnetostatic wave element and a conductor disposed on the top of said magnetostatic wave element. Because the width of an junction portion of the conductor is larger than the width of an input portion of the conductor, a large impedance change of the magnetostatic wave element at resonance can be obtained while maintaining a Q-value at a high level.

Abstract: A matching network is to be provided which can quickly and easily be tuned to a desired impedance. The matching network has a first and a second line which are interconnected at one end, while their other ends are coupled to a microwave line, and a third line which branches off from the interconnection of the other two lines. The first and/or second line and the third line are loaded with ferrite. The ferrite of the first and/or second line and that of the third line are exposed to separate magnetic fields which can be varied independently of each other.

Abstract: An interdigital capacitor (10) is provided including a plurality of conductive and dielectric finger regions. The conductive finger regions are made of the same material type as a microstrip transmission line (12). The conductive finger regions are comprised of individual conductive fingers (14) and the individual conductive fingers (14) provide a predetermined level of impedance to the microstrip transmission line. The plurality of conductive finger regions are comprised of a first finger region (18) and a second finger region (20). The first finger region (18) is coupled to the microstrip transmission line (12) and the second conductive finger region (20) is coupled to ground (22). The individual conductive fingers (14) of the first conductive region (18) are located parallel and interspersed with the individual conductive fingers (14) of the second conductive finger region (20).

Abstract: A source of microwave power is connected to the first, input, port of a six-port device whose second, output, port is connected to a device under test. A variable impedance is connected between the source and the input port. Preferably, the variable impedance is a mechanical three stub tuner. The six-port device includes a first directional coupler whose first input comprises the input port and whose first output comprises the output port. First, second and third hybrid couplers have outputs which constitute the third, fourth, fifth and sixth outputs of the six-port device. A power divider connects the directional coupler to the hybrid couplers.

Abstract: A coaxial microwave device, such as a microwave switching device, for example, having improved thermal and power handling characteristics. At least one thermally conductive short-circuit element is located between inner (input and output) and outer conductors of the microwave coaxial or switching device. Consequently, heat losses generated in the inner conductors are conductively channeled away from heat sensitive materials. Typically, quarter-wavelength elements provide a thermal path to reduce heat buildup, thus enabling the microwave coaxial device or switching device to operate at higher RF power levels without overstressing components or materials. However, short circuit elements having element lengths other than one-quarter-wavelength may be employed to offset mismatches in a transmission line, for example. Furthermore, the short circuit elements may be used singularly or in pairs to provide for improved thermal and power handling characteristics in the devices in which they are used.

Abstract: This composite electronic part comprises a dielectric layer on which earth electrodes are formed, a dielectric layer on which conductive lines are formed, and a dielectric layer on which electronic parts are pattern-formed. A plurality of the dielectric layers are so laminated that the dielectric layer with the earth electrodes is disposed next to the dielectric layer with the conductive lines. These conductive lines and earth electrodes form strip lines. A short-stub or an open-stub is formed by connecting one end of the conductive line to the earth electrode or opening that one end. A composite electronic part is obtained by connecting the short-stub, open-stub, and the electronic parts.

Abstract: A miniature, electrostatically actuated, dynamically tunable circuit which is operable to tune a transmission line in response to control signals. This circuit is micromachined with the use of integrated circuit processes such that a fixed transmission line is fabricated on a substrate and a movable signal line is fabricated over the substrate and is movable relative to the fixed transmission line in response to electrostatic fields produced when the control signals are selectively applied to an array of air bridge stator control electrodes which span the transmission line.

Abstract: A miniature, electrostatically actuated, stub tuner which is operable to dynamically tune a transmission line in response to control signals. With the use of integrated circuit processing the transmission line is fabricated on a substrate and at least one stub tuner is fabricated over the substrate and is movable relative to the transmission line in response to electrostatic fields produced when the control signals are selectively applied to rows of control electrodes.

Abstract: A monolithic microwave integrated circuit device provides a microwave transmission line with a resistor coupled thereto and a heating element thermally coupled to the resistor but electrically insulated therefrom by a dielectric layer. Heating the resistor with the heating element causes either a change in resistance of the resistor or the generation of noise by the resistor. Either the resistor or the heating element is constructed using monolithic integrated circuit construction techniques on the same circuit substrate with the transmission line.

Abstract: A PIN diode switch employing an active switching field emission device having high intrinsic isolation to high frequency and microwave frequency energy signals and exhibiting integratability is provided.

Abstract: A device for tuning a circuit includes a substrate, a transmission line on the substrate that includes first and second conductors coupled to a circuit to be tuned, and a movable short-circuit for varying the impedance the transmission line presents to the circuit to be tuned. The movable short-circuit includes a dielectric layer disposed atop the transmission line and a distributed shorting element in the form of a conductive member that is configured to be slid along at least a portion of the transmission line atop the dielectric layer. The conductive member is configured to span the first and second conductors of the transmission line and to define at least a first opening that spans the two conductors so that the conductive member includes first and second sections separated by the first opening.

Abstract: A superconductive array antenna system provides a substantial improvement of gain, in the range of from about 5 db to over 20 db, at frequencies in excess of 20 gigahertz, and preferably in the range from 40 to 100 gigahertz and beyond. The antenna system includes a phased antenna array, operating at superconductive cryogenic temperatures, with superconductive phasing and switching systems, to permit antenna beam steering and polarization independent of operating frequencies. The invention also permits the elimination of amplifiers and other such elements that have been needed to overcome system losses, and permits further miniaturization of such systems.

Abstract: A ferrite tuning arrangement for a resonator includes a ferrite loaded line in the form of a stripline having an inner conductor, an outer conductor and a ferrite disposed between the inner and outer conductors, with the stripline being adapted for coupling to the resonator. A reflecting termination is provided for the stripline and a magnetic circuit is provided for generating a variable premagnetization field for the ferrite in an orientation perpendicular to a high frequency magnetic field existing in the stripline.

Abstract: Disclosed is a microwave circuit suitable made into a monolithic microwave integrated circuit (MMIC). This microwave circuit includes a main line comprising a distributed constant line formed on a major surface of a substrate, and a stub connected in parallel with the main line in which lines the characteristics admittance varies discontinuously. Because of the discontinuous variation of the characteristic admittance of the stub, the phase of the characteristic admittance is changed, so that the stub length can be reduced.

Abstract: A magnetostatic wave device comprises a magnetic thin film formed on a non-magnetic substrate, one or a plurality of electrode fingers and pad electrodes formed on the above described magnetic thin film, a magnetostatic wave resonator for exciting and propagating a magnetostatic wave within said magnetic thin film and for causing resonance, and a matching stub connected to at least one of the above described pad electrodes of the above described magnetostatic wave resonator to adjust the impedance of the magnetostatic wave device.

Abstract: A device for propagating microwave energy to a plasma discharge tube from an antenna coupled to a microwave generator includes a hollow rectangular conduit and a strip-line resonator or strip-line conductor disposed therein. The discharge tube is mounted perpendicular to and through a central opening in the strip-line resonator and is disposed at a distance, from one end of the strip-line where the antenna is located, of one-half the wavelength of the microwave energy and one-quarter wavelength from the opposite end. The strip-line is attached to one end of the rectangular conduit and is supported by a dielectric member at a point one-quarter wavelength from the antenna. Microwave energy is propagated from the antenna by the strip-line dimensioned to the resonant frequency of the microwave the energy. A gas, such as argon or helium, is introduced into the discharge tube and is ionized by microwave energy to form a plasma.

Abstract: An automatic load-matching circuit for microwaves, disposed on a transmission line between a signal source and a load. Signal detection means for detecting a travelling wave component and a reflected wave component and for producing outputs corresponding to the absolute value of reflection coefficient .GAMMA., the cosine products .vertline..GAMMA..vertline. cos .theta., and the sine product .vertline..GAMMA..vertline. sin .theta. for controlling an automatic matching means, which includes three matching elements, each having an adjustable short-circuit length, disposed on the transmission line with a separation of odd number multiples of 1/8 of a wavelength along the transmission line. The first and third matching elements are connected such that in response to a change in the short-circulating length of one of the first and third matching elements, the short-circuiting length of the other of the first and third matching elements changes in a corresponding opposite manner.

Abstract: A resistive film attenuator element comprised of a dielectric-mounted resistive film distributed ladder network having tuning stubs, combined in a coplanar structure, to provide a wide band attenuator having a substantially flat frequency response over a wide range of frequencies, for example, from D.C. to 40 GHz.

Abstract: A programmable microwave network test device is capable of establishing a multitude of reflection and transmission coefficients determined by a set of digital inputs. The programmable network enables the collection of groups of measurements which are used to characterize a non-linear or linear device. The microwave structure of the network is comprised of a series of PIN diodes interconnected through microstrip transmission lines. The lengths of the transmission lines between the PIN divide are proportioned so as to allow use of the network over a broad frequency range, with a minimization of repeated reflection coefficients in a use of the network, the device to be characterized would be placed at the input port of the network with the output port of the network terminated in its characteristic impedance.

Abstract: The invention relates to a stripline circuit comprising at least one stripline pattern (2 to 6) made of a material of high electrical conductivity on the surface of a printed board (1) made of a dielectric material, a metallic or metal coated cover (8 to 12) being provided in the vicinity of the stripline pattern in an electrically non-conducting manner with respect to it, and the distance of the cover (8 to 12) from the stripline pattern being adjustable to regulate the characteristic impedance of the stripline. In order to simplify practical circuit solutions, each cover (8 to 12) is integral with a casing (7) protecting the printed board (1).

Abstract: The invention relates to a stripline circuit comprising a stripline structure of a high-conductive material disposed on the surface of a board of a dielectric material, as well as a method for regulating such a stripline circuit. The invention is characterized in that a metallic or metal coated cover (4) is non-conductively provided in the vicinity of the stripline structure (2), the distance of the cover from the stripline being adjustable to regulate the characteristic impedance of the stripline. The distance of the cover from the stripline is preferably adjusted by bending the cover (4).

Abstract: Disclosed is a tunable circuit for an integrated circuit device and a process for making such circuit.

Abstract: An electrical short-circuit for alternating-current (ac) microwave signals is physically positionable in direct response to an electrical bias control without an intermediary electromechanical converter. The electrically positionable short circuit includes at least first and second doped regions in a semiconductor, separated by a region in which the short circuit is formed between the doped regions by the bias. A first embodiment comprises discrete diodes connected between conductors at different locations, the discrete diodes having different forward junction voltages, so that varying the common bias voltage varies the number of conducting diodes and thus positions the short circuit in a stepwise manner.

Abstract: A lower-noise microwave amplifying circuit for use in a lower-noise converter includes a metallic conductor for use in performance adjustment. The metallic conductor projects from the microstrip line and is provided near a bendable connecting portion between an input coaxial rod in a coaxial waveguide conversion portion and a microstrip line for constructing one portion of an amplifying circuit. Therefore, the lower-noise microwave amplification circuit is easily adjusted for improving the basic characteristics such as input VSWR or the like and is simpler in construction.

Abstract: An electrohydraulic servo system which includes a linear actuator having a cylinder and a piston variably positioned therewithin, a servo valve responsive to valve control signals for coupling the actuator to a source of hydraulic fluid, and control electronics responsive to piston position for generating the valve control signals. A coaxial transmission line is formed within the linear actuator to include a center conductor coaxial with the actuator and an outer conductor. A bead of ferrite or other suitable magnetically permeable material is coupled to the piston and surrounds the center conductor of the transmission line for altering impedance characteristics of the transmission line as a function of position of the piston within the cylinder.

Abstract: A ceramic TEM resonator bandpass filter with varactor tuning is disclosed. The varactor is located within the resonator holes of a ceramic TEM resonator filter, and is positioned within said holes immediately above the upper extent of the metal plating forming the resonator in said resonator holes. The placement of the varactor in such a manner reduces the interference caused by the varactor in the interresonator coupling. A new apparatus for positioning the varactor within the resonator hole is disclosed and basically includes a conductive rod which at its top end receives the varactor.

Abstract: The invention relates to a device for the fine adjustment of a resonant microstrip-line formed on an insulating substrate (2), tuned by a varicap diode (7,8) which makes it possible to adjust the shape of the curve representing the tuning frequency of the strip line as a function of the direct voltage controlling the diode. One or more blind holes are provided in the surface of the substrate opposite the strip line, and a base part (15) with one or more threaded holes, into which cylinders are screwed, is fitted under the strip line. The cylinders are placed facing the blind holes and are aligned with the holes to enable entry into them. The cylinders and the base part are electrically conductive and connected to ground.

Abstract: A dielectric filter (FIG. 16) for frequencies higher than VHF band comprising a closed conductive housing (112), a pair of input and output means provided at both the extreme ends of said housing (112), a dielectric body (111) with a plurality of linear parallel grooves (118) arranged in said housing (112), a plurality of conductive linear means (113) with the length of approximately 1/4 wavelength mounted in said dielectric body (111) between said grooves (118) so that one end of said resonators (113) is fixed to the common plane of the housing (112), a capacitor means (114, 115) provided between the other end of resonators (111,113,118) and said conductive housing (112) so that an electrode (115) of said capacitor may be trimmed by a laser beam to adjust the resonating frequency of each of said resonators (111,113,118) and a plurality of conductive rods (137) provided in said grooves (118) for improving the spurious characteristics of the filter.

Abstract: Transmitter combining apparatus includes up to five RF filters (100) coupled to a microstrip combiner (300) for combining up to five input signals for application to a common antenna. The RF filter (100) includes a ceramic resonator (116) sandwiched between first and second compensating discs (114 and 120) and first and second shield plates (142 and 148) for temperature compensation, low loss mounting and heat sinking of the ceramic resonator (116). Good thermal contact between the ceramic resonator (116), discs (114 and 120) and shield plates (142 and 148) is produced by a compressive force exerted by springs (144-147) of shield plate (142) when the top cover (112) is attached to the aluminum housing (124). The resonant frequency of the RF filter is tuned by means of an aluminum tuning shaft (102) and ceramic tuning core (118) which are positioned by brass bushing (133) in top cover (112).

Abstract: A microwave tuning device including a cylindrical metal bush having an internal screw thread. A metal rod-like plunger is axially displaceable within the plastics bush. A plastics bush is fitted over one end of the plunger and fixed thereto by means of splines and grooves. The bush is inserted into the internal screw thread so as to form a corresponding mating screw thread on its outer periphery. A plurality of fingers extend from one end of the metal bush and resiliently engage the outer periphery of a plain portion of the plunger so as to provide resistance to unintentional rotation of the plunger in the metal bush and electrical interconnection therebetween.

Abstract: Impedance adjusting elements for a microstrip circuit of the kind employing a signal transmission line connected to an active circuit element and impedance matching elements, such as parallel-connected open-ended stubs, are formed of one or more wire elements arranged in proximity to the transmission line and the open-ended stub and connected at one end to the ground plane on the side of the substrate opposite the transmission line, wherein the free end of the wire elements can be freely moved, thereby adjusting the spacing of the wire elements from the respective signal path and open-ended stub and adjusting the angle of intersection of the wire elements and the respective signal path and open-ended stub, so that the effective impedances of the circuit can be controlled.

Abstract: A television broadcast transmitter includes two power amplifiers or transmitters, a dummy load and an antenna. A noncontacting switching arrangement includes directional couplers or hybrids operated as controllable phase-shifters under the control of pairs of variable reactive terminations. Signals arriving at the antenna or load port by two paths combine in-phase to couple signal to that port, or combine out-of-phase to cancel signal. If the out-of-phase condition is inaccurate, cancellation may be incomplete, resulting in crosstalk. To avoid the need for accurate positioners to position the variable reactive termination at the position providing the desired phase-shift, a particular structure of the reactive termination is used. The reactive termination is a short-circuited coaxial line with an axial gap in the center conductor at a position less than one quarter operating frequency wavelength from the short circuit.

Abstract: A strip-line resonator comprises a first dielectric substrate having a conductive film on one surface thereof for connection to ground and a strip line on the other surface thereof and a second dielectric substrate having one surface thereof making contact with the strip line and a conductive film on the other surface thereof for connection to ground. Fused glass having a low melting point for is applied between the first and second substrates to bond them together. A portion of open-circuit end of the strip line is exposed and formed with slits or gap to facilitate frequency adjustment.

Abstract: A coaxial short-circuit device has an inner conductor which is surrounded by an outer conductor and is electrically connected to the latter by a shorting plunger. In order to allow the axial movement of the shorting plunger, the inner conductor accommodates a spindle which is connected in a force-locking manner to a first carriage arranged between the spindle and the inner conductor. A second carriage is arranged between the inner and the outer conductor and cooperates with the first carriage in such a manner that upon rotational movement of the spindle the first carriage is axially shifted along the spindle and this movement is transmitted to the second carriage and eventually to the shorting plunger which is connected to the second carriage in a force-locking manner.

Abstract: A coupling arrangement for a cavity resonator (10), in particular for measuring the magnetic resonance of a sample (17) located within the cavity resonator (10) comprises a loop (14) for supplying a radio frequency signal to the cavity resonator (10) and exciting in the latter a specific mode of oscillation. For optimizing the coupling of the radio frequency signal, mechanical means are provided, preferably in the form of an axially adjustable screw (16), which permit the surface of the loop (14) to be varied mechanically, and the loop (14) is capacitively coupled with the resonator housing.

Abstract: In a microwave device, particularly a microwave local oscillator, frequency variations due to temperature changes are reduced by supporting the tuning element, for example a quartz or sapphire crystal, in the end of a tube of INVAR or other material having a low thermal coefficient of expansion. The tube projects into the cavity from a hole in one wall thereof. Preferably the tube is positively located relative to the cavity by means of an external lip on the tube abutting a shoulder formed by a reduced diameter part of the hold adjacent the cavity. The lip may be urged into positive contact with the shoulder by a spring washer acting between the end of the tube and the opposed end of a bush screwed into the hole.

Abstract: A microwave circuit device package including a conductive housing and selectively interchangeable transmission line sections each one thereof being disposable in such housing and means for tuning and matching the impedance of the disposed transmission line section to the impedance of a device connected thereto over a relatively wide frequency band of applied signals. Such tuning means includes a conductive member of predetermined dimensions slidably mounted in proximity to a selected conductor portion of one of such transmission line sections. Such transmission line sections include a straight continuous in-line configuration for high frequencies or serpentine strip conductor configurations for low and intermediate frequencies, each one of such serpentine strip conductor configurations defining a different acute angle relative to the conductive member. The microwave circuit housing is used to test, calibrate, evaluate or characterize the properties of the connected device over the wide frequency bandwidths.