Microwave Modules Research Articles

Hexagonal ferrites for self-biasing circulators integrated in LTCC microwave modules

Next-generation microwave LTCC modules for satellite communication systems require the integration of passive components including circulators to manipulate electromagnetic signals at high frequency. Substituted M-type hexagonal ferrites (Ba/Sr)ScxFe12−xO19 are applied as self-biasing microwave magnetic materials at frequencies of about 30 GHz. The ferrites are integrated into LTCC multilayer devices as sintered drop-in bulk samples. Sintered ferrites with preferential orientation of grains were fabricated by compaction of powders in a magnetic field and sintering at 1300 °C. Alternatively, screen-printed ferrite films were dried in an external magnetic field, and cofired at 900 °C. The magnetic texture of the ferrites is characterized using XRD, EBSD, and magnetic measurements. Integrated Y-type circulators were tested and exhibit non-reciprocal behavior. This indicates that hexagonal ferrites are promising candidates for self-biasing circulators embedded in LTCC microwave modules operating at Ka-band frequencies at around 30 GHz.

Investigation of the profilogram structure of microstrip microwave modules manufactured using additive 3D-printing technology

Objectives. The aim of the work is to study the surface roughness of the current-carrying topology and dielectric of the upper (Top Layer) and lower (Bottom Layer) sides of microwave modules manufactured using additive three-dimensional printing technology when prototyping prototypes of microwave modules on a 3D printer of DragonFly 2020 LDM multilayer printed circuit boards.Methods. Methods of metallographic analysis in bright and dark fields, surface roughness profiling, and computer modeling were used.Results. Experimental samples of microstrip microwave elements of modules of multilayer boards of a given configuration, telemetry sensors, printed circuit board (PCB) antennas were obtained. The topological and radiophysical features of the additively formed upper and lower surface layers of experimental samples of boards of strip modules were studied. Optical profilogram measurements of the roughness of the outer sides of the board were carried out at 10 points, amounting to 2 µm for the upper layer of the topology and 0.3 µm for the lower layer; the average grain size of the dielectric base was determined at 0.007 mm2. The roughness of the conductive topology and upper side dielectric was shown to correspond to an accuracy class of 6–7, while the roughness of the microstrip conductive topology and the dielectric of the lower side of the board corresponds to an accuracy class of 10–12.Conclusions. It is established that an uneven formation of the lower and upper strip layers of the printed module can affect the inhomogeneity of the distribution of radiophysical parameters (dielectric permittivity, surface conductivity, etc.), as well as the instability of the structural (adhesion ability, thermal conductivity, etc.) characteristics of the strip module, which must be taken into account when prototyping devices using inkjet 3D printing technology, including when adapting Gerber projects of PCB modules created for classical board production technology.

Wafer-Level Au—Sn Solid-Liquid Interdiffusion Bonding for Microwave Applications

Future compact integration of microwave modules will require intermetallic bonding with pitch connections lower than 10 μm. Solid-liquid interdiffusion (SLID) bonding is a potential bonding method for close heterogeneous integration because of its bonding temperature in the range of solder bonding, its ability to withstand higher temperaturs than bonding and its moderate compatibility with the joining of rough surfaces. This paper presents the results of an investigation of the Au—Sn system for integration of A3B5 chips on wafer level using SLID bonding. A sequence of five layers of Au and Sn with weight ratios of about 3:2 was deposited on a sapphire substrate. The structure and phases of the obtained system were investigated before and after annealing. The initial system has five distinctive alternating layers with an overall thickness of around 4.5 μm. After heat treatment at 320 °C with a holding time of 10 minutes, the Au—Sn system transforms into one layer that consists of only one phase ζ (Au0.853Sn0.147). The homogenization process is completed in less than 10 minutes. The ζ phase, of which the system is composed after annealing, has a melting point of 522 °C, which ensures the high temperature stability of the bonding layer. Bonding using the formed system was conducted. Morphology, elemental composition, and the initial mechanical properties of bonded structures have been studied. There are two types of defects in the joint's cross section: voids and the presence of local interfaces between two surfaces (an unbonded-like line). EDX analysis of the cross section of the joint between two crystals shows that the average ratio of Sn to Au over the cross section of the joint is 10.7 %. The complex of studies conducted suggests that the bonding area mostly includes the ζ phase, which will provide the best mechanical strength characteristics among the phases with a high Au concentration. The average bond shear strength is 32 MPa. Initial robustness results of the bonding are promising for space applications.

Eliminate Costly Component Out Of Pocket Defect Condition during Microelectronic Component Packaging/Shipping/Handling

High value devices used in microwave modules and other microelectronic assemblies have become increasingly thin and susceptible to “Component Out Of Pocket” (COOP) conditions that can occur during packaging, shipping, and customer handling. This defect condition is especially problematic for automated assembly which strives to be touch-free and efficient with orderly device presentation. COOP is a major contributor to “Cost Of Poor Quality” (COPQ) within the business. A funded study into COOP conditions was conducted and a dozen root causes were identified. It was discovered that traditional “waffle packs” have mechanical issues related to flatness tolerances with respect to the waffle tray and lid. The addition of a standard clip further contributes to the issue, both of which are key root causes of the costly “Component Out Of Pocket” (COOP) condition. A novel Lid-Clip System (LCS2) was engineered to compensate for those mechanical issues, bringing robust captivation and preservation of devices in waffle tray pockets. Static dissipative material for lid and clip was selected to provide unparalleled ESD Class 000 protection for high value devices with the lowest voltage susceptibility thresholds.

Accelerated Production of Biopharmaceuticals via Microwave-Assisted Freeze-Drying (MFD).

Recently, attention has been drawn to microwave-assisted freeze-drying (MFD), as it drastically reduces the typically long drying times of biopharmaceuticals in conventional freeze-drying (CFD). Nevertheless, previously described prototype machines lack important attributes such as in-chamber freezing and stoppering, not allowing for the performance of representative vial freeze-drying processes. In this study, we present a new technical MFD setup, designed with GMP processes in mind. It is based on a standard lyophilizer equipped with flat semiconductor microwave modules. The idea was to enable the retrofitting of standard freeze-dryers with a microwave option, which would reduce the hurdles of implementation. We aimed to collect process data with respect to the speed, settings, and controllability of the MFD processes. Moreover, we studied the performance of six monoclonal antibody (mAb) formulations in terms of quality after drying and stability after storage for 6 months. We found drying processes to be drastically shortened and well controllable and observed no signs of plasma discharge. The characterization of the lyophilizates revealed an elegant cake appearance and remarkably good stability in the mAb after MFD. Furthermore, overall storage stability was good, even when residual moisture was increased due to high concentrations of glass-forming excipients. A direct comparison of stability data following MFD and CFD demonstrated similar stability profiles. We conclude that the new machine design is highly advantageous, enabling the fast-drying of excipient-dominated, low-concentrated mAb formulations in compliance with modern manufacturing technology.

Numerical and experimental investigations of a microwave interferometer for the negative ion source SPIDER

The electron density close to the extraction grids and the co-extracted electrons represent a crucial issue when operating negative ion sources for fusion reactors. An excessive electron density in the plasma expansion region can indeed inhibit the negative ion production and introduce potentially harmful electrons in the accelerator. Among the set of plasma and beam diagnostics proposed for SPIDER upgrade, a heterodyne microwave (mw) interferometer at 100 GHz is currently being explored as a possibility to measure electron density in the plasma extraction region. The major issue in applying this technique in SPIDER is the poor accessibility of the probing microwave beam through the source metal walls and the long distance of 4 m at which mw modules should be located outside the vacuum vessel. Numerical investigations in a full-scale geometry showed that the power transmitted through the plasma source apertures was above the signal-to-noise ratio threshold for the microwave module sensitivity. An experimental proof-of-principle of the setup to assess the possibility of signal phase detection was then performed. The microwave system was tested on an experimental full-scale test-bench mimicking SPIDER viewports accessibility constraints, including the presence of a SPIDER-like plasma. The outcome of first tests revealed that, despite the geometrical constraints, in certain conditions, the phase detection, and, therefore, electron density measurements are possible. The main issue arises from decoupling the one-pass signal from spurious multipaths generated by mw beam reflections, requiring signal cross correlation analysis. These preliminary tests demonstrate that despite the 4 m distance between the mw modules and the presence of metal walls, plasma density measurement is possible when the 80 mm diameter ports are available. In this contribution, we discuss the numerical simulations, the preliminary experimental tests and suggest design upgrades of the interferometric setup to enhance signal transmission.

Effects of Au/Ni coating thickness on enhancing the properties of InPb/MoCu solder joints in microwave modules

Deep understanding of and effective improvement in interconnect performance are of great significance for developing miniaturized and high-performance microwave modules. Herein, the effects of Au/Ni coating thickness on the performance of InPb interconnect solder joints were investigated by the high-temperature storage experiment. At normal Au/Ni joints, the AuIn2 intermetallic compound (IMC) particles bordered on each other, attributing to form a “closed zone” where the diffusion rate of In atoms was faster than that of Au atoms and there was a net flux. Here, the vacancies in the “closed zone” were merged in reaction to form Kirkendall voids. However, the “closed zone” inside the thin Au/Ni joints could be greatly reduced, and thus the generation of voids was significantly suppressed. The diffusion coefficient of AuIn2 IMCs was reduced by 22.34% at the thin Au/Ni joints compared with the normal Au/Ni joints. After aging for 168 h, the shear strength of the thin Au/Ni joints was increased by 25.10% compared with the other one. Therefore, the thin Au/Ni coating could enhance the long-term performance of solder joints in microwave modules and meet the development requirements of microwave module miniaturization.

Integrated Microwave and mm-Wave MIMO Antenna Module With 360° Pattern Diversity for 5G Internet of Things

The complete coverage of the operating frequency bands from microwave bands to millimeter (mm-wave) is required for the realization of the fifth-generation (5G) Internet of Thing (IoT) systems. Here, we present a multiband antenna operating at the microwave (2.5/3.5/5.5/7.5 GHz) and mm-wave bands (23–31 GHz), and its 12-port MIMO configuration with pattern diversity affording 360° coverage for 5G IoT applications. The multiband characteristics are obtained by adding well-designed quarter-wavelength stubs. The antenna operates at the important frequency bands from 2.37–2.65, 3.25–3.85, 5.0–6.1, and 7.15–8.5 GHz (|S11| <–10 dB), while it resonates from 23–31 GHz at the mm-wave band with the desired radiation characteristics. Moreover, the antenna has more than 95% radiation efficiency and a stable gain (> 2.5 dBi at microwave band and 6.5 dBi at mm-wave bands) characteristics. In addition, the single-element antenna is translated to design a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2\,\,\mathbf {\times }\,\,2$ </tex-math></inline-formula> MIMO antenna. This MIMO unit is further utilized in the formation of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2\,\,\mathbf {\times }\,\,4$ </tex-math></inline-formula> and the proposed <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$3\,\,\mathbf {\times }\,\,4$ </tex-math></inline-formula> (12-port) MIMO configurations to achieve spectral and pattern diversity. Considering the unique three-dimensional arrangement of the antenna elements, the 12-port MIMO system is the only one of its kind that offers the codesign of microwave and mm-wave antenna, good isolation, and pattern diversity, providing complete 360° space coverage in elevation and azimuth planes. The proposed antenna module is suitable for 5G IoT, especially in an indoor scenario for smart houses, offices, and vehicle-to-everything communications.

Analytical and 3D Numerical Study of Multilayer Shielding Effectiveness for Board Level Shielding Optimization

The strong development of solid-state power sources offers numerous benefits (such as higher operating frequencies and reduced switching times and power losses), but contributes inherently to the extended range of electromagnetic interferences (EMI). As these systems are associated with a set of embedded monitoring devices using low amplitude signals, it becomes necessary to consider new critical cases of electromagnetic (EM) immunity correlated to such environments. The most common solution against aggressive radiated EMI is the metallic enclosure, which brings a strong shielding effectiveness (SE), but is it always the best compromise? Our study in this paper is focused on the SE of multilayer designs and is therefore intended to optimize the enclosures’ compactness for board level shielding (BLS) on printed circuit boards (PCB). First, results are presented, based on metallic multilayer shielding theory and parametric numerical studies in the intentional electromagnetic interferences (IEMI) frequency range, from 0.2 to 5 GHz. Then, a complete 3D EM co-simulation model using the microwave and design modules of CST Studio Suite (which includes the subject, the EMI radiating source, and the multilayer shielding) is proposed, with emphasis on the pertinent choices regarding layers width and their arrangement for compact EM shielding and immunity optimization.

МИКРОВОЛНОВЫЕ ПОЛЯРИЗАТОРЫ НА ОСНОВЕ ПЕЧАТНЫХ ДИФРАКЦИОННЫХ РЕШЕТОК МЕАНДРОВОГО ТИПА

The problem of printed gratings application is considered as converters of electromagnetic wavespolarization and polarizing modulators. Two directions in development of antenna engineering areconsidered in this paper. In each of them the scattering fields control of an antenna arrays allows essentiallyto expand functionalities of radio engineering sets. The first direction is the creation of auxiliarydepolarizing reflectors for two-mirror reflector antennas and folded lenses. In addition, in meanderlinepolarizers based on printed gratings, it is possible to constructively realize the necessary phase distributions of the field on their surfaces. Thus, it becomes possible to use such meanderline polarizers to createmultifunctional microwave antenna radomes. The second direction is connected to application ofantenna arrays for a reduction of a radar cross section of the radar-tracking targets. Transformation ofa field polarization by an antenna array allows to achieve both these purposes. In an aspect of high costand complexity of arrays experimental researches as a method of the analysis the mathematical simulationis selected. Besides, it is shown that introduction of impedance loads in the construction of the reradiatingelements of the printed grating opens additional possibilities for controlling the field scatteredby it. Thus, meanderline polarizers with improved characteristics can be realized on the basis ofmicrostrip-pin gratings. The given results can be used for choosing the most of rational electrodynamicstructure geometry variant at decision of particular problems by antennas engineering. The possible flatarrays based on printed complicated shape elements application area is also discussed and it's shownthese arrays are the very attractive type for controllable radioelectronic covers designing at microwaves.Some numerical results presented prove the possibility of a printed arrays application as smartcovers microwave modules.

Application of autodynes in advanced systems of atmosphere radar sensing

The results of studies of an autodyne transceiver (AT) for advanced radar sensing systems of the atmosphere are presented. A mathematical model of the APP has been developed, presented in the form of an oscillator with a single-circuit oscillatory system under the influence of a request signal from the radar. The analysis of the dynamics of signal reception in the beat mode, when the frequency of the received signal is outside the synchronization band, as well as in the capture mode, when the frequency of the request signal falls into the synchronization band of the AT. The noise and energy parameters and characteristics of the microwave generators used as an AT are investigated. Calculations of dynamic, noise and energy parameters and characteristics of the AT are performed depending on the choice of the type of conductivity characteristic of the active element and the position of the working point on it, as well as on the conditions of connection of the AT with the load. The experimental studies of the AT were carried out on the example of a serial transistor microwave module of the MRS-3MK radiosonde at a frequency of 1680 MHz. The description of the structural scheme of the AT for an aerological radiosonde operating in the beating mode is given. It is shown that the sensitivity of the AT to the request signal is determined by fluctuations in the amplitude of the microwave module and the bandwidth of the intermediate frequency amplifier. It is established that the sensitivity of the AT is minus 110...120 dB/W, for measuring the inclined range of 250...300 km is enough to have a radar transmitter with a pulse power of 50...100 W, while its average power corresponds to 0.05...0.1 W.

Integrated design of monolithic integrated circuits of microwave modules

Integrated design of monolithic integrated circuits of microwave modules

Simple and Effective Design Concept for Constructing In-Situ Soil Dielectric Property Sensor With Dual Low-Cost COTS Microwave Modules

Simple and Effective Design Concept for Constructing In-Situ Soil Dielectric Property Sensor With Dual Low-Cost COTS Microwave Modules

Compact and Integrated Microstrip Antenna Modules for mm-Wave and Microwave Bands Applications

This paper presents two different antenna modules at two different bands with a compact size structure that is used for both of mm-Wave and microwave bands, with the objective of keeping the size as minimum as possible. The presented structure consists of two integrated modules with overall dimensions of 24 <inline-formula> <tex-math notation="LaTeX">$\times 15\times0.787$ </tex-math></inline-formula> mm³ and is implemented on a Rogers RT5880 substrate. The first module is designed to resonate at 25.75 GHz with bandwidth of 4.15 GHz. The length of this module is taken as a constraint in designing the second module, which is the microwave one. This module is designed to have resonance frequency of 5.45 GHz with bandwidth of 1.12 GHz. The two modules are etched on the same substrate in an integrated fashion to give the required structure with two separate feeds and a separation gap between them in the ground plane. The proposed antenna structure is simulated using the CST-MW studio simulator, where it is found that for the mm-Wave module, the band&#x2019;s gain is 5.58 dBi and the efficiency is 0.87 at 25.75 GHz. As for the microwave module, the gain is 2.45 dBi and the efficiency is 0.77 at 5.45 GHz. The proposed structure is implemented practically and the relevant measures agree with the simulated ones. A comparison of the proposed structure with other designs available in literature shows that it exhibits the minimum size among them, while keeping the other parameter values of comparable orders. The proposed structure is suitable for being used in 5G applications where both of the microwave and millimeter- wave bands are utilized.

Diagnostics of solid-state microwave modules at the initial stage of technological tests

Process testing is an integral part of the production of solid-state microwave modules used in radar stations. At the final stage of production, long-term technological tests are carried out. However, at the initial stage of testing, it is possible to carry out diagnostics of solid-state microwave modules, which makes it possible to identify malfunctions leading to failures of solid-state microwave modules.

Eliminate Costly Component Out Of Pocket Defect Condition during Microelectronic Component Packaging/Shipping/Handling

Abstract High value devices used in microwave modules and other microelectronic assemblies have become increasingly thin and susceptible to “Component Out Of Pocket” (COOP) conditions that can occur during packaging, shipping, and customer handling. This defect condition is especially problematic for automated assembly which strives to be touch-free and efficient with orderly device presentation. COOP is a major contributor to “Cost Of Poor Quality” (COPQ) within the business. A funded study into COOP conditions was conducted and a dozen root causes were identified. It was discovered that traditional “waffle packs” have mechanical issues related to flatness tolerances with respect to the waffle tray and lid. The addition of a standard clip further contributes to the issue, both of which are key root causes of the costly “Component Out Of Pocket” (COOP) condition. A novel Lid-Clip System (LCS2) was engineered to compensate for those mechanical issues, bringing robust captivation and preservation of devices in waffle tray pockets. Static dissipative material for lid and clip was selected to provide unparalleled ESD Class 000 protection for high value devices with the lowest voltage susceptibility thresholds.

Mechanical Design and Manufacturing of Signal Interception Antenna in Composite Material for Naval Application

This work shows the mechanical design and the FE analyses performed for an innovative naval Antenna Unit for signal interception application: more than twenty electromagnetic sensors operating from HF up to Ka band and microwave modules are integrated in a unique structure designed for a top mast installation (i.e. for naval platform). The number of constraints in terms of weight and electromagnetic transparency calls for the employment of composite materials such as glass, aramidic and carbon epoxy prepregs. Primary structures was modelled by using FE codes: both orthotropic and isotropic models have been implemented as well as non-linear contacts and bolted joints. The mast-mounted installation requires high mechanical stiffness and strength but the exposure to saline environment needs many manufacturing issues to be respected. In particular, the selection process of suitable materials and the sealing manufacturing procedures to protect them from the external agents was reported. Another key feature of the presented design concerns the electromagnetic compatibility requirement: to avoid electromagnetic emissions (EMC) generated by antenna’s internal units and to protect antenna sensors by external platform’s emitters, an appropriate stacking sequence was chosen for composite laminates with a prepreg copper mesh.

Development of an innovative rotating spiral heat exchanger with integrated microwave module for the olive oil industry

A new prototype of an integrated tube-in-tube heat exchanger with rotating spiral coil and microwave module is proposed. The prototype was installed in an industrial olive oil extraction plant and tested to determine how much it improved overall extraction performance of the plant and olive oil quality.Nominal mass flow rate showed that the prototype was perfectly integrated in the plant. Thanks to the transport action of the rotating spiral coil, the prototype did not affect the feed pressure of the olive paste from the crusher to the malaxer. Using the heat exchanger, malaxing time was reduced by 50% without decreasing oil extraction. The microwave module increased oil extractability.The new prototype applied to mechanical extraction of virgin olive oil enhanced the quantitative and qualitative composition of hydrophilic phenols without altering legal quality parameters or significantly modifying the volatile fraction.

Comlexed RF-module with synchronized generators M-type

On the basis of previously carried out works [2, 3], it has been established that the most effective way for coherent summation of the power of two generators with a waveguide output is to use a waveguide 3-decibel bridge as an adder. In this case, the output power of the synchronized device within the synchronization band can reach 95% of the total power of the generators. Purpose of the work is to describe the installation «microwave module», which uses the method of coherent summation of the powers of two magnetrons in the power adder. Mutual phased synchronization of two magnetrons is provided by a phase shifter, matching is provided by a short-circuiting piston. The summed signal is sent to the output (antenna) path of the radar. The microwave generator module is designed to generate probing pulse signals in a multifunctional receiving-transmitting radar measuring complex. For the first time in Russia, JSC «Pluton» has created a «microwave module» installation in the 2-centimeter wavelength range, which makes it possible to use the principle of coherent addition of the powers of two commercially available magnetrons. The installation cost and manufacturing time are many times less than those for a newly developed magnetron with the parameters presented in this article.

Устройство экранирования элементов СВЧ-модуля многослойной платы для приемо-передающего модуля АФАР космического назначения

A method of shielding the elements of a microwave module based on the principles of forming a Faraday cage, with different power and different frequency paths of the AFAR receiving-transmitting module, excluding their mutual electromagnetic influence, is presented. A description of the structure of a multilayer board and various structural elements is given, allowing to limit (screen) the signal in a small volume, commensurate with the size of a monolithic integrated circuit or a set of monolithic integrated circuits, isolating parasitic electromagnetic interference. Polyimide is considered as a dielectric material of a multilayer microwave board for use in space technology devices, as well as promising design solutions for reducing the mass and dimensions of the module.