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In this article, a simple and accurate method is proposed to extract the sheet resistance of a thin conductive film by using the enhanced one-port waveguide in a microwave frequency. A shorted quarter-wavelength waveguide is supplemented to the main waveguide as its open boundary to ensure the TE10 mode during the measurement. Unlike the available waveguide with the metal flange, the dielectric flange of the shorted quarter-wavelength waveguide is proposed to eliminate the transverse electromagnatic (TEM) wave propagation and leakage in the gap between two waveguide flanges. The conductive film deposited on the substrate is attached to the main waveguide flange, and the equivalent circuit model is generated thereof. By measuring S 11 parameters of the bare substrate and conductive film with the substrate, respectively, the unknown sheet resistance of the conductive film can be easily extracted. Even a large sheet resistance could be measured accurately. Both numerical and measurement results are presented for effectiveness validation of the proposed method. In comparison with the available dual-port method and waveguide with the metal flange method, the dielectric flange raises the measurement accuracy sharply in aspects of substrate thickness, substrate materials, and sheet resistance.

We propose a metasurface (MTS) structure integrated at the aperture of a flanged rectangular waveguide to produce dual-beam radiation. The dual beams are antiparallel in an orientation and perpendicular to the boresight direction. The MTS is backed by a dielectric slab to produce a substrate integrated waveguide-like response above the flange. The MTS is engineered to limit the boresight emission from the waveguide aperture, as well as to allow symmetric wave splitting between the MTS and waveguide flange. A lens-like end texturing involving surface tapering and electromagnetic bandgap cells is utilized to enhance the beam directivity at endfire from the flange. The dual-beam radiation exists for all frequencies between 10.5 and 12.4 GHz. The proposed design is modeled via full-wave simulation in commercial software, then validated through the measurement of a fabricated prototype.

In this work, a WR-1.5 band-pass filter is presented, manufactured using the Polystrata 3D fabrication process. The filter is intended to be integrated into a radiometric receiver to band limit the incoming noise power and encompass an atmospheric spectral window centered at 682.5 GHz. A 10.8 mm diameter waveguide flange is fabricated in Polystrata with a band-pass filter structure running parallel to the flange face. The thickness of this standalone filter “shim” is 0.8 mm. The dimensions of the filter structure itself are 0.4 mm x 0.8 mm x 2.3 mm. The filter has a 3 dB bandwidth of 12 GHz, or 1.7%, and exhibits 4.5 dB insertion loss. These results are compared against standard CNC machine split-block waveguide iris filters at the same frequency to highlight the advantages of micromachined filters for terahertz applications.

Good electrical contact is always required between waveguide flanges of the test system and DUT to minimize leakage and losses that will degrade circuit performance. This requires the DUT to be tightly and carefully connected to avoid gaps and mismatches. This can be time consuming, especially when performing repeated measurements on multi-port devices. In this paper we present a contactless flange that can be used at millimeter-wave (mmW) and terahertz (THz) frequencies. Unlike conventional waveguide flanges, the contactless flange can be used to perform fast measurements because normal flange screws are not required. An E-band prototype has already been successfully designed, manufactured, and tested. The use of contactless waveguide flanges allows for faster, accurate, and reliable mmW and THz measurements.

Passive intermodulation (PIM) measurement is necessary for microwave and antenna products to evaluate their PIM performance. To achieve stable low residual PIM level of measurement system and make accurate PIM test, a compact waveguide flange adapter is proposed based on gap waveguide, dielectric filled bed of nails is adopted to construct compact double-sided artificial magnetic conductor (AMC) structure. When the adapter is connected between standard waveguide flanges, double-sided contactless electromagnetic band gap (EBG) structure with air gap is formed inside the flange connection. Electromagnetic leakage is prevented by stop band of the EBG structure. Meanwhile, metallic contact nonlinearity is almost eliminated by the contactless structure, and PIM can be therefore suppressed. A Ku band prototype of the adapter is designed for a Ku band PIM measurement system. By using the adapter, the system’s residual PIM is significantly improved with a maximum improvement better than 30 dB, achieving a stable low level.

The purpose of the study was to analyze the basic technological process of manufacturing waveguide flanges at PJSC “ALMAZ R&P Corp.” LEMZ Division. A method for optimizing the process has been proposed, and a theoretical study using the finite element method has been carried out. The stress-strain state of the forging of a complex shaped flange during its manufacture with closed bulk forming has been analyzed as well.

The ITER Electron Cyclotron Heating Upper Launcher (ECHUL) will be used to drive current locally inside magnetic islands located at the q = 2 (or smaller) rational surfaces in order to stabilize neoclassical tearing modes (NTMs). Each of the fours antennas consists of eight beam lines, totaling 12.8 m that are designed for the transmission of up to 1.5 MW of mm-wave power at 170 GHz, with at least 90% of the power in the main HE11 mode. Each transmission line consists of a Z shaped set of straight corrugated, aluminum alloy waveguides connected by miter bends with a nominal inner diameter of 50 mm. The FCS system also encompasses intrinsic components such as: closure plate, mm-waveguide taper, isolation valve, diamond window and an EU-US interface waveguide. All FCS components are connected via a dedicated flange coupling, with a bolted connection, comprising of two concentric metallic seals in order to satisfy the SIC-1 requirements. The coupling shall be capable of resisting the applied external loads and displacements, including thermal cycles due to ohmic losses in the transmission line, and also adhere to the matting of different materials (EN AW-6082, CuCrZr, SS 316L) while maintaining ultra-high vacuum tightness (10 −8 mbar). The present study will use a dedicated experimental apparatus for the characterization of the mechanical and vacuum properties of a single metallic seal under compression, with applied heat flow. In order to ensure reproducibility of the components mechanical characteristics, randomly chosen metallic seals of each diameter have been tested from two independent manufactures (A and B).

Contact nonlinearity is one of the primary sources of passive intermodulation (PIM). Common methods to eliminate the contact nonlinearity are focused on improving the electrical contact. In this letter, the contactless waveguide flange (CWF) based on gap waveguide technology is first applied to solve the PIM problem caused by waveguide connection. A compact folded CWF is proposed for low-frequency applications. The artificial magnetic conductor plate, in the form of a bed of nails, is arranged surrounding the outer surface of the male flange, whereas a waveguide with broader hollow end serves as the female flange. The size of the proposed contactless flange is significantly reduced compared to its planer counterpart. An S-band prototype is designed, manufactured, and measured. Compared to traditional waveguide flange, the measured PIM level achieves a maximum improvement of 30 dB, which is almost unaffected by surface plating materials and connection pressure.

In this paper, Minimization of Flange effect and antenna transmit to receive isolation improvement using RF choke in Slotted Waveguide Array antenna is presented. In slotted waveguide antenna, the mounting of waveguide to the flight vehicle is done by using a waveguide flange. The flange causes variation in the antenna Radiation pattern, and increase in Side lobe level and thereby degrading the performance of antenna. An RF Choke adjacent to the waveguide wall, is used to nullify the undesirable effects of the flange. The comparison of simulated results with and without the flange and with and without choke are presented. It is observed that the quarter wave length groove called choke, at certain distance from waveguide wall, along the length of the waveguide improves the radiation pattern, isolation and SLL, hence reduces the flange effect. It is observed that the antenna properties of slotted waveguide antenna with flange and choke approximately matches with the antenna properties of slotted waveguide antenna without flange and choke. It is observed that presence of choke also improves the Isolation from transmit to receive antenna.

A new method of realising precision waveguide shims for use in THz Through-Reflect-Line (TRL) calibrations, based on silicon-micromachining, is introduced. The proposed calibration shims combine a thin λ/4 silicon layer, co-fabricated with a thicker layer which provides mechanical support. This design overcomes the limitations of CNC milling for the creation of calibration shims, facilitating use of standard TRL calibration at currently challenging frequencies. The novel shim fits inside the inner recess of a standard waveguide flange and is compatible with conventional flange alignment pins. Five micromachined shims were fabricated in a silicon-on-insulator process for operation in the WM-570 waveguide band (325–500GHz). The fabricated shims show excellent performance across the entire band, with return loss in excess of 25dB, insertion loss below 0.2 dB and high uniformity between samples. Verification reveals that the micromachined shims have an electrical length within 2% of the expected value. Comparative measurements of a DUT calibrated with the proposed shim and a previously un-used conventional metallic shim show that the novel concept offers equivalent, if not better, performance. The mechanical design of the micromachined shim and the rigid nature of silicon ensure that it will not suffer from performance degradation with repeated use, as is problematic with thin metallic shims. This work enables the creation of low-cost, highly-repeatable, traceable calibration shims with micrometer feature-sizes and high product uniformity, surpassing the limits of current techniques. QC 20190903. QC 20191219

Landmines still pose a serious threat mostly to civilians. Therefore, there is no doubt that working on the methods of landmines’ detection and liquidation should be considered extremely important. In this paper, we introduce the active infrared thermography with microwave excitation used in nonmetallic landmines’ detection. The effectiveness of the method is strongly dependent on the manner in which microwaves illuminate the ground. In this paper, we propose a new waveguide flange’s construction, which guarantees the uniform field distribution, and through this, a relatively uniform microwave heating on a certain area. The flange’s shape is based on box-horn. Its dimensions will be determined using a hybrid optimization algorithm. Results obtained in an optimization process will be validated using the numerical models. The experiments showing flange’s efficiency, concerning heating of sand itself and sand with buried landmines, will also be presented.

Contactless waveguide flange is a novel structure to prevent leakage of electromagnetic wave when it propagates across the waveguide flange. The main advantage of contactless waveguide flange is electrical contact of the connected waveguides is not required as long as the gap between the adjacent flanges does not exceed the maximum permitted distance. Therefore, relative motivation or rotation of the contactless connected waveguides is possible. The contactless waveguide flanges have been reported are all planar. A cylindrical contactless flange is first proposed. Then, a novel flexible rectangular waveguide is proposed based on it. A Ka-band prototype is successfully designed and manufactured. The prototype consists of two bendable contactless flange joints. The maximum bending angle of each joint is limited to ±8° to maintain the return loss performance. The number of joints can be easily increased if larger bending angles are needed. The insertion loss and return loss at different bending angles are measured. The measured insertion loss is better than 0.7 dB from 26 to 37 GHz, and is better than 1.8 dB from 37 to 40 GHz. The measured return loss is 15 dB except frequencies around 37.5 and 40 GHz.

Current waveguide flange standards do not allow for the accurate fitting of microchips, due to the large mechanical tolerances of the flange alignment pins and the brittle nature of Silicon, requiring greatly oversized alignment holes on the chip to fit worst-case fabrication tolerances, resulting in unacceptably large misalignment error for sub-THz frequencies. This paper presents, for the first time, a new method for directly aligning micromachined Silicon chips to standard, i.e. unmodified, waveguide flanges with alignment accuracy significantly better than the waveguide-flange fabrication tolerances, through the combination of a tightly-fitting circular and an elliptical alignment hole on the chip. A Monte Carlo analysis predicts the reduction of the mechanical assembly margin by a factor of 5.5 compared to conventional circular holes, reducing the potential chip misalignment from 46 μm to 8.5 μm for a probability of fitting of 99.5%. For experimental verification, micromachined waveguide chips using either conventional (oversized) circular or the proposed elliptical alignment holes were fabricated and measured. A reduction in the standard deviation of the reflection coefficient by a factor of up to 20 was experimentally observed from a total of 200 measurements with random chip placement, exceeding the expectations from the Monte Carlo analysis. To our knowledge, this paper presents the first solution for highly accurate assembly of micromachined waveguide chips to standard waveguide flanges, requiring no custom flanges or other tailor-made split blocks.

A novel simple approach to the verification process for millimeter-wave vector network analyzer waveguide cal- ibration is reported using a single reconfigurable component verification kit. Conventional techniques require multiple verifica- tion components and these only exist commercially for operation up to 110 GHz. At millimeter-wave frequencies, the use of multiple components can lead to significant errors due to imperfections in waveguide flange misalignments during the multiple component connections. The reconfigurable component is designed so that its electrical properties can be changed quickly to a broad range of predetermined values without introducing additional errors due to changes in flange alignment. Once connected, the component can be reconfigured to introduce relative changes in the reflected and transmitted signals. For millimeter-wave metrology, where mechanical precision is of paramount importance, this single-com- ponent verification approach represents an attractive solution. A proof-of-concept verification process is described, based on full-wave electromagnetic modeling, hardware implementation, and validation measurements using standard WR-15 waveguide (50-75 GHz).

Nondestructive evaluation of stratified (layered) composite structures at microwave and millimeter-wave frequencies is of great interest in many applications where simultaneous determination of the complex dielectric properties and thicknesses of multiple layers is desired. Open-ended rectangular waveguide probes, radiating into such structures, are effective tools for this purpose. The technique utilizes a full-wave electromagnetic model that accurately models the complex reflection coefficient as a function of frequency and material properties. While the electromagnetic model assumes an infinite waveguide flange (or ground plane), the measurements are conducted using a finite-sized flange. Consequently, the results of the electromagnetic model and those from measurements may not be sufficiently alike for accurate dielectric property and thickness evaluation. This paper investigates the effect of using an open-ended waveguide with a standard finite-sized flange on the error in evaluating the complex dielectric properties of a composite structure. Additionally, we present the design of a novel flange that markedly reduces this undesired effect by producing very similar electric field properties, at the flange aperture, to those created by an infinite flange. Finally, the efficacy of the design for evaluating the dielectric properties of a layered composite structure is demonstrated as well.

This paper describes a computer vision based robotic waveguide flange alignment system that achieves improved repeatability of waveguide measurements. The proof-of-concept is demonstrated using WR-62 in the frequency band 12.40 GHz to 18 GHz. An Arduino board was used to interface a three-channel NTS NanoDirect XYZ positioner with MATLAB and its image acquisition toolbox. The measured results of a back-to-back adapter pair demonstrate significantly improved repeatability with the automated system compared with manual alignment. Through EM modelling of two WR-1.0 rectangular waveguides over the frequency range 800 GHz to 1 THz it is shown that this new method for enhancing measurement repeatability will be invaluable.

Measurements with waveguide flanges at frequencies above 100GHz have a considerable issue with leakage due to problems with achieving good electrical contact between the opposite flanges. The higher the frequency, the higher is the requirement for full contact. However, by using an artificial magnetic conducting (AMC) flange on one side of the interface, full electric contact is not needed between the two joining flanges. The AMC is realized as a pin-surface, and the leakage is stopped by a parallel-plate stopband like in gap waveguides. This paper describes how these AMC pin waveguide flanges can be used for screw redundant measurements.

[EN] In this paper, the generation of passive intermodulation at rectangular waveguide flange bolted connections is investigated. An exhaustive series of tests has been performed in order to provide understanding on the physics lying behind such a phenomenon. In particular, the intermodulation response of the system has been studied as a function of the applied torque to the flange screws. It has been found that, in some situations, the intermodulation response differs from its expected behavior. An interpretation of such discrepancies is given, and practical guidelines for the design of waveguide flanges free of passive intermodulation are provided as well., This work was supported by the European Space Agency under the Surface Treatment and Coating for the Reduction of Multipactor and Passive Intermodulation Effects in RF Components Project, by the European Space Research and Technology Centre under Contract 17025/03/NL/EC, by the Generalitat Valenciana (Spain) under PREDECTOR Project IIARC0/2004/020, and by the Spanish Government (MEC) under a Juan de la Cierva Program Fellowship.

Connection repeatability is mainly dependant on flange tolerances and aperture misalignment. A waveguide flange design establishing precise connections has been developed for use at millimeter and sub-millimeter wave frequencies up to 1.1 THz [1, 2]. Other research groups have investigated the misalignment effect of waveguide apertures on electromagnetic performance at the interface [3]. This paper describes simulation results of connection repeatability for waveguide TRL “through” line standards with two different sizes of aperture, undersized and about the same size when compared to a test-port aperture, in the WM-864 (WR-3, 220 GHz-330 GHz) frequency band. Comparisons between simulations and measurements are described.

An innovative waveguide flange offers superior alignment based on a concentric mating mechanism consisting of a boss and jack interface. Above 100 GHz, this flange interface improves repeatability and precision of S-parameters measurements by eliminating the mechanical tolerance build-up associated with separate alignment pins. By simplifying the build-up of tolerance to only the boss and jack interface, the alignment improves match, precision, repeatability and residual calibration performance for mm-wave and sub-mm-wave S-parameter measurements. This flange is entirely compatible with the MIL-DTL-3922/67D standard. This paper presents connection repeatability for 220–325 GHz (WR-03 band). This flange is awaiting standardization in the P1785 working group of IEEE.

Waveguide flanges are typically used to connect and measure high frequency circuits. When good conductive contact is not provided between the joining flange surfaces, currents will flow between them, and thereby causing leakage and losses affecting the circuit performance. This work presents a non-leaking contactless waveguide flange made with bed of nails. The flange does not need any contact when connected to another smooth flange, since the pins surface and the smooth surface together form a stopband suppressing any current and wave propagation between the two joining surfaces of the flanges.

The active infrared thermography, using external energy source to produce a thermal contrast between the feature of interest and the background, is relatively new NDT technique. The microwaves applied in this method as the source of energy, effectively shorten the time needed to receive observable thermal image at the surface of examined specimen. In this paper, above method's application to landmines' detection will be considered. In this case, the microwave generator, connected to rectangular waveguide is used to heat the ground's surface. Obtained thermal pattern should be characterized by uniform temperature distribution. This condition can be met by applying an appropriate waveguide flange, ensuring an even distribution of EM field. In this article genetic algorithm-based optimization will be applied to determine the box-horn based flange's dimensions.

Waveguide flange design makes major impact to measurement reproducibility in the range of millimeter and sub-millimeter-wave frequencies, e.g. above 110 GHz. Original concept of flange design, so-call “Oshima” flange, was established in the early 2000s. Its flange alignment is ensured using ring with tight tolerance, however, it is not compatible to MIL-DTL-3922/67C (UG-387) flange. This paper describes a modification of “Oshima” flange in order to establishing a compatibility with UG-387 flange design, and evaluation result of its capability of connection repeatability in the WR-3 (220 GHz–330 GHz) frequency band. Furthermore, the quarter wave length shim, as a TRL “through” line standard, is specially modified to fit with a new design of “Oshima” flange, then, its capability of connection repeatability is also measured and discussed.

Existing waveguide flanges impose a major limitation on measurement precision above ≃100 GHz. A ring-centered waveguide flange was proposed in [1, 2] and its electrical performance characterized in the WR-5 band. This paper explores an improved ring-centered waveguide flange which is backward compatible with the original UG-387 flange and with all its known variants, and facilitates standard TRL VNA calibration using a properly aligned "through" waveguide shim. The modifications to the ring-centered waveguide flange are discussed and measurements in the WR-2.2 (330–500 GHz) band presented.

Flush mounted aperture antennas are widely used and are often approximated by an aperture in an infinite conducting surface. The equivalent circuit parameters for the canonical problem of a rectangular waveguide radiating into a half-space (i.e., an infinite conducting flange) is equivalent to that for the parallel plate guide but using the guide wavelength. In 1951 Marcuvitz obtained an approximate solution by the variational method assuming a constant aperture field [1]. Since then this canonical problem has received much attention with solutions obtained by various rigorous, approximate and numerical methods. Here we select some of the published results for comparison to numerical results obtained by the Method of Moments (MoM) using FEKO and the Finite Element Method (FEM) using Ansoft's HFSS. The analytic results are based on the correlation matrix (CM) [2], transverse operator (TO) [3] and an integral equation method (KP) [4]. Although rigorous, these methods can be complicated and assume an infinite, zero-thickness conducting flange. To address realistic and possibly conformal antenna installations a numerical model is typically more accurate and more useful for antenna design. To this end FEKO is used to simulate a rectangular waveguide in a finite size flat plate for a single incident TE 10 mode. HFSS is used to simulate the waveguide with an infinite conducting flange. The results are used to estimate how large a waveguide flange is required to approximate the HFSS and previously published results for an infinite flange.

The cell for measurement of dielectric permittivity is intended for research of properties of water solutions in the range of temperatures from 0 to 70°C in a range of frequencies of 30–40 GHz. The simplified construction of a cell is presented on Fig.1. The cell consists of the camera for solution and insert. The camera for a solution consists from waveguide flange with a segment of a circular waveguide 1, capacities for a solution 2, insert for the thermometer 3 with an entry branch pipe for flood filling of a solution, an output branch pipe for change of a solution 4. The segment of a circular waveguide has round deepening for glass tight laying from side capacities for a solution. The insert consists from waveguide a flange with a segment of a circular waveguide 5 and tanks 6 with a cylindrical part. The tank has round deepening for glass tight laying from side capacities for a solution also. Glass tight layings are pasted compound glue. The camera and an insert are made of stainless steel and incorporate by screws. Laying from high-temperature moisture resistant rubber is allocated between the camera and an insert for hermetic connection. The camera and insert have plane side surfaces. Heating units are attached to these surfaces by means of slices. The heating unit represents twelve ceramic resistances (on six cells from each side) with admissible power of 10 Watt everyone and with rating value of 72 Ohm. Resistances are connected in a parallel way. For cell heating the heating unit was connected to an alternating voltage source which regulated a range from 5 to 10 Volt so that speed of heating of a solution in a cell was no more than one degree for two minutes.

Waveguide flanges pose a major limitation to precise measurements above 110 GHz. This paper describes measurements on a new flange which is compatible with the standard UG-387 waveguide interface (MIL-DTL-3922/67C) but which offers significant improvement in alignment and repeatability. The ring-centered flange has a precisely machined boss centered on the waveguide aperture. The bosses of a mated pair of flanges are aligned by a separate coupling ring. The new flange is sexless and the contact surfaces are accessible for mechanical lapping to repair damage. Measurements of WR-5 waveguides (140–220 GHz) with ring-centered flanges, enhanced UG-387-type flanges, and a new flange proposed by Lau and Denning are compared.

An inherent problem with waveguide interface above 110 GHz is waveguide flange misalignment. This misalignment occurs as the result of machining tolerances. Under the current MIL SPECS specified tolerances and the standard alignment pins to alignment holes method, the smaller the waveguide, the greater the relative misalignment and the greater the impact to the system electrical performance. At 680 GHz, the flange and the waveguide can be misaligned as much as a quarter (?) wavelength - that is, half (1/2) the physical waveguide dimension. This paper describes an innovative waveguide interface design that offers improved performance repeatability, VSWR frequency response and a more robust mechanical handling without the use of conventional alignment pins to alignment holes technique. Integrated into the design are ease of manufacturing and ease of alignment. The uniqueness of the novel waveguide interface is discussed and the performance of the WR-05 (140 GHz to 220 GHz) waveguide interface is presented.

This paper deals with design and development of high power RF window for S-band linear accelerator at spot frequency 2.856 GHz which is capable of handling peak and average powers of 6 MW and 25 kW, respectively, with VSWR and insertion loss 1.1 and 0.1 dB, respectively. The HFSS software is used for computation of diameter and thickness of ceramic and other required parameters. Further, analytical technique is used for calculation of inner diameter of water pipe for effective cooling. All parts of window are fabricated. The window is assembled and tested. The theoretical values of VSWR, insertion loss, and return loss are found in good agreement with corresponding experimental values. Further the effect of variation of thickness, dielectric constant of ceramic and frequency is also studied and it is found that VSWR, insertion loss and return loss are affected. The output parameters are computed with the help of HFSS software. The inner diameter of the adopter used for cooling is calculated with the help analytical technique and it is found to be 5 mm. The essential parts of the window are ceramic, ceramic holding circular waveguide, outer circular waveguide with water adopter, standard waveguide flange, and UHV conflate flange.

We present the first micromachined double-sided contactless WR03 pin-flange adapter for 220-325 GHz based on gap waveguide technology. The pin-flange adapter is used to avoid leakage at the interface of two waveguides even when a gap between them is present and can be fitted onto any standard WR03 waveguide flange. Tolerance measurements were performed with gaps ranging from 30-100 mu m. The performance of the micromachined pin flange has been compared to a milled pin flange, a choke flange and to standard waveguide connections. The micromachined pin flange is shown to have better performance than the standard connection and similar performance to the milled pin flange and choke flange. The benefits of micromachining over milling are the possibility to mass produce pin flanges and the better accuracy in the 2D design. Measurements were performed with and without screws fixing the flanges. The flanges have also been applied to measure two devices, a straight rectangular waveguide of 1.01 inch and a ridge gap resonator. In all cases, the micromachined pin flange performed flawlessly while the standard flange experienced significant losses at already small gaps.

The influence of the waveguide flange, frequency of operation and liftoff on crack detection sensitivity using the dominant mode as well as the higher-order mode approaches are presented. The results indicate that the optimal choice of these parameters can significantly enhance crack detection sensitivity in practical applications.

A variety of approaches to the design of flanges for millimeter waveguide use coupled with the research nature of the work in this field has made standardization a difficult rask. Shortly after World War II, cover flange designs similar to the UG 385/U shown in Fig. 1 were designed (U. S. Army Air Force at Watson Laboratories). This flange design was intended to provide intimate contact across the important broadwalls of the waveguide and precise alignment of the interior sections of the waveguide by the alignment pins. Also, by means of an "O" ring groove provided around the round section, pressurization of these flanges is possible. Thus, with an asexual flange design, the problem of male or female flanges was eliminated and it appeared that a universal design was at hand.

This paper discusses factors affecting the accuracy of Vector Network Analysis in millimeter waveguides. Among these are accuracy improvements provided by a new precision WR15 waveguide flange which maintains compatibility with the current UG-385/U flanges. The new wR15 waveguide flange design offers much improved performance in the frequency range of 50 to 75 GHz. Measurement results for flange repeatability along with accuracy results for residual directivity and source match, both for Maury and UG-385/U standard flanges, are presented.

The four electron cyclotron (EC) upper port antennas (or "upper launchers" -UL) will be used to drive current locally inside magnetic islands located at the q= 2 (or smaller) rational surfaces in order to stabilize neoclassical tearing modes (NTMs), as well as heat inside of p of about 0.4. Each antenna consists of eight beam lines that are designed for the transmission of 1.5 MW of mm-wave power at 170 GHz. The First Confinement System (FCS) is formed by the ex-vessel mm-wave waveguide components, for which SIC-1 classification requirements apply. The beam lines in the FCS comprise a Z shaped set of straight corrugated waveguides with a nominal diameter of 50 mm connected by miter bends. This system is subjected to imposed displacements coming mainly from the thermal expansion of the vacuum vessel, seismic events and/or plasma disruption events. In absence of suitable SIC-1 waveguide bellows, the FCS waveguides must provide the necessary mechanical functional compliance. This has required the development of a dedicated, flange type coupling system with double metallic seals, capable of resisting the generated external loads while maintaining vacuum tightness and alignment. This paper presents the results of the design, analysis and pre-qualification experimental work done on the waveguides and the integrated SIC-1 compliant coupling system. (C) 2016 Elsevier B.V. All rights reserved.

A compact quick-release hydraulic waveguide flange clamp is described which is at least four times faster than the usual flange nuts and bolts used to assemble and disassemble waveguide components during precision measurements. An integral pressure gauge ensures repeatability of the clamping force.