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Several designs of lossy filters for receivers in satellite transponders have been investigated in order to improve the performance in terms of flatness compared to a classical hairpin filter design. Flatness and insertion loss performances for all solutions are summarized. The reference design is a microstrip filter made of coupled hairpin resonators. Two approaches have investigated for improving the flatness of the reference design. Lossy filter designs have been compared to the reference, considering the same specifications and the same technology. An in-line network with resistive cross-couplings and a transversal network with heterogeneous Q resonators have been designed and fabricated first. Theoretically, the transversal network leads to better performances in terms of flatness, but its implementation is generally difficult, especially considering the input/output junctions between multiple paths, which are naturally dispersive, causing spurious transmissions in the stopband. Moreover, a Monte Carlo analysis has been performed, showing higher sensitivity of this later solution with respect to manufacturing tolerances. Consequently, considering measured performances, in-line networks with resistive cross-couplings appear to be the best solution for implementing our receiver filter. In particular, the version with two RCCs appears as a good compromise between flatness and insertion loss. Finally, the in-line network has been transformed introducing non-resonant nodes and additional resistive cross-couplings in order to design absorptive lossy filters. The resulting filters allow attenuating the reflected wave substantially with a reduced impact on the absolute level of losses.

This paper introduces an effective way to build efficient miniature C-band filters using high-permittivity ceramics. The objective was to evaluate the feasibility of such filters using commercial electromagnetic simulators and a conventional fabrication process. For the demonstration, the substrate integrated waveguide (SIW) technology was chosen. Compared with planar solutions, this configuration offers good quality factors and good electrical performances as a consequence. However, its dimensions are large, leading to unacceptably large footprints for many applications. The solution proposed in this paper is based on a ceramic substrate with a permittivity of 90, which allowed us to work with shorter wavelengths. In comparison with a standard alumina substrate (permittivity $\varepsilon _{r}= 9.9$ ), this approach makes it possible to reduce the footprint up to nine times. Two prototypes were realized on a Trans-Tech ceramic substrate ( ${\rm thickness}=635~\mu \text{m}$ , $\varepsilon _{r} = 90$ , and tan $\delta = 9\cdot 10^{-4})$ . The first prototype is a folded sixth-order SIW filter including a cross coupling combining coplanar waveguide probes and a thin microstrip line on an InterVia substrate. The second one is a folded eighth-order SIW filter without cross couplings. Here, we compare the sixth-order prototype with an identical one built on alumina. The eighth-order filter, which had no alumina counterpart, is a potentially useful alternative for situations where complex technological steps must be avoided.

This paper proposes a new solution for implementing high-quality-factor tunable filters, suitable for high-power handling. The dual-mode filter is realized with a cylindrical cavity, which comprises metallic lugs and is loaded by a dielectric element. The center frequency is tuned between two states, by adjusting mechanically the position of the lugs within the cavity. The lugs allow modifying the capacitive effect between the dielectric element and the cavity for adjusting the resonant frequency.

This paper outlines an original shape optimization library backed by a three dimensional (3D) full-wave electromagnetic (EM) simulator, combining several efficient structural optimization techniques and suitable for viable computer-aided design (CAD) of complex microwave components. The microwave components are modeled by finite element method (FEM) and their dimensions and shape are optimized using four techniques: design of experiments (DOE), level-set method (LS), topology gradient (TG) method, and genetic algorithm (GA). The various methods allow determining the optimal geometry, shape or topology of 2D or 3D objects within the microwave device, by minimizing iteratively a cost function related to the desired specifications. Typical demonstration illustrates the versatility of the proposed library based on the design of a dual mode dielectric resonator filter in order to improve its unloaded quality factor by keeping the same frequency isolation, their accuracy and efficiency are verified by the available measured results.

In this paper, the design of compact diplexers with dual-mode cavities for satellite payloads is detailed. Compact diplexers are composed of coupled resonators without additional waveguide element, leading to a more compact architecture. Two topologies are first implemented and compared with a standard manifold output diplexer, in terms of electrical performances, compactness, and power handling. Hardware prototypes are fabricated and measured for experimental verification. A third topology is finally introduced for the design of noncontiguous diplexers. © 2013 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:249-258, 2014.

For output multiplexer (OMUX) filters placed in telecommunication satellites, microwave breakdown happens in an involuntary and undesirable way during tests at atmospheric pressure. This avalanche phenomenon is due to exponential growth of the electronic density caused by thermoelectronic emission under strong electromagnetic field magnitude. In this paper, our objective is to model and characterize experimentally multipole OMUX filters composed with coupled cavities. For identifying the element responsible for the breakdown, the electric field is calculated within each cavity and each iris. In order to characterize the breakdown phenomenon, we proposed an experimental test bench and we measured the power, both at the input and at the output of the filter. The article details the theoretical breakdown prediction and the experimental setup for such a structure. © 2013 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:46–54, 2014.

In this paper, the design of compact diplexers and triplexers with dual-mode cavities is presented. Such devices are composed of coupled resonators without additional waveguide element, leading to a more compact architecture. Two topologies of compact diplexers are implemented and compared to a standard manifold diplexer. A hardware prototype is fabricated and measured for experimental verification. A compact triplexer is finally introduced for extending the concept to more than three ports.

This article presents a procedure for the design of bulk acoustic wave (BAW) filters. The procedure consists of optimizing the modified Butterworth-Van Dyke model of each resonator, considering appropriate technological parameters. The approach is demonstrated first to design a classical aluminum nitride-based BAW filter but remains valid for other piezoelectric layers, considering either longitudinal or transverse acoustic wave coupling. The approach is finally applied to the design of a lithium niobate (LiNbO3) BAW filter for wide-band filtering applications. © 2011 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2011. © 2011 Wiley Periodicals, Inc.

This paper compares several designs of lossy filters for receiver subsystems in satellite transponders. The reference design is a microstrip filter made of coupled hairpin resonators. Two approaches are investigated for improving the flatness of the reference design. The first approach combines nonuniform quality factor (Q) resonators in a transversal network. The second approach uses an inline network with resistive cross couplings. Lossy filter designs are compared to the reference, considering the same specifications and the same technology. The inline network with resistive cross-couplings is finally modified for designing absorptive filters, which protect the receiver from reflected waves. All filter configurations are fabricated and measured, showing a good agreement with electromagnetic simulations.

This paper deals with the microwave breakdown phenomenon that can appear in output multiplexer filters for telecommunications satellites. The first objective of this paper is to describe summarily the phenomenon. The second objective is to validate the theoretical modeling by experimental tests on a realistic example. A two-channel OMUX at Ka band has been designed and built and a dedicated measurement procedure has been proposed. As it will be shown, the experimental results agree well with the theoretical one.

This paper deals with the microwave breakdown phenomenon that can appear in output multiplexer filters for telecommunications satellites. In order to model this phenomenon a multidisciplinary approach with a combination of three fields of science was used: electromagnetism, thermal transfer theory and plasma physics. In this article we resume the theoretical study and we present our experimental validation.

International audience

International audience

International audience

International audience; In this paper, an original self-equalized filter and a compact diplexer are presented. New methodologies for synthesizing and designing these devices are introduced. Implementation in dual-mode cavities is preferred since this technology offers compactness and good electrical specifications required for space applications.

In this paper, we report the printing of multilayered structures mixing silver nanoparticles and low temperature fired ceramics based inks. The conductivity of the silver ink is characterized up to 20GHz and above, and the typical performances of the technology and used dielectric material are given. A metallo-dielectric printed capacitance is finally presented as a first demonstrator.

Filters based on film bulk acoustic resonators (FBARs) are widely used for mobile phone applications, but they can also address wideband aerospace requirements. These devices need high electromechanical coupling coefficients to achieve large band pass filters. The piezoelectric material LiNbO3 complies with such specifications and is compatible with standard fabrication processes. In this work, simple metal—LiNbO3—metal structures have been developed to fabricate single FBAR elements directly connected to each other on a single chip. A fabrication process based on LiNbO3/silicon Au-Au bonding and LiNbO3 lapping/polishing has been developed and is proposed in this paper. Electrical measurements of these FBAR filters are proposed and commented exhibiting filters with 8% of fractional bandwidth and 3.3 dB of insertion losses. Electrical measurements show possibilities to obtain 14% of fractional bandwidth. These devices have been packaged, allowing for power handling, thermal, and ferroelectric tests, corresponding to spatial conditions.

While characterizing OMUX filters at atmospheric pressure, electrical breakdown can occur involuntarily and damage the equipment. The phenomenon of breakdown was studied and our objective was to propose a multi-physical modeling, in order to predict the critical input power which can generate such a microwave breakdown. In this paper we present the microwave breakdown threshold at several frequency bands and we propose a solution to relax the microwave breakdown threshold.

In this paper, we propose a compact dual-band microwave output diplexer for the next generations of communication satellite. For reducing bulk, the designed diplexer is exclusively composed of coupled resonators and channel filters realize dual-band filtering functions. Compared to classical multiplexing architectures, the proposed design eliminates additional waveguide elements and leads to a more compact device. On the other hand, dual-mode cavity implementation is chosen for getting more compactness, and suiting with payloads output multiplexers, since this technology is largely used for OMUX applications.

A Ku band 6 pole quasi-elliptic filter based on dielectric resonators is presented. To the best of our knowledge, this is the first time that temperature stable BMT ceramic material (er = 24.4 and tan δ = 0.95.10−4 ± 0.29.10−5 at 11.1 GHz) is associated with stereolithography process for the manufacturing of 3D parts. The proposed filter is composed of 6 dielectric resonators, their support and a dielectric negative coupling element all connected into one single ceramic part. This configuration is optimized to achieve a 1.7% pass band at 11.7 GHz which does not require any glue or advanced positioning technique for its assembly into silver cylindrical cavities. A 41% volume reduction compared to standard 6 pole TE113 cavity filter is proposed while keeping a Qu of 8500 and insertion loss close to −0.3 dB.

International audience; This paper presents a C-band planar filter miniaturized through use of high-permittivity substrates to meet the specifications. The drawbacks associated to such substrates are briefly recalled. To overcome them, the filter under study was based on the DBR topology and realized on a high-K commercial substrate. This ceramic has a relative permittivity of 90 and a low dielectric tangent (tanδ

This article describes the development of a library of computer-aided-design (CAD) optimization techniques for advanced design of microwave components. The microwave components are modeled by finite elements and their dimensions and shape are optimized using four methods: design of experiments (DoE), level-set method (LS), topology gradient method (TG) and genetic algorithm (GA). The various techniques allow determining the optimal geometry, shape or topology of 2D or 3D objects within the component, by minimizing iteratively a cost function related to desired specifications. These global and local optimization methods are coupled together resulting in an optimization library where the various techniques can be selected successively in order to acquire a much better result compared to methods applied solely. The approach is illustrated by the design of dielectric resonators with improved unloaded quality factor.

This paper proposes, for the first time to the best of our knowledge, two challenging LTCC multi-pole bandpass filters operating at 150 GHz for radioastronomy applications. Low-temperature co-fired ceramic (LTCC) technology is employed to realize these filters because it assures the high precision and compactness needed at this high frequency. The two filters are optimized by 3-D electromagnetic simulations and are validated by experimental results. Different positive and negative couplings, which are achieved by different coupling apertures, are studied. The five-pole Chebyshev filter has 8.4 dB of insertion loss in a 1.31% fractional bandwidth for 6.7 mm × 2.45 mm lateral dimensions. The four-pole quasi-elliptic filter is conceived to decrease insertion loss by decreasing the number of resonant cavities while conserving the same selectivity by introducing two transmission zeros around the passband. Beside 5.5 dB of insertion loss, this filter occupies a more compact circuit area (3.32 mm × 2.37 mm) and insures a very good spurious free region (16 GHz) around 150 GHz. Experimental results are in good agreement with the theoretical ones and validate the use of LTCC technology at such high frequencies over 100 GHz.