Laetitia Estagerie

Quasi-Elliptic and Chebyshev Compact LTCC Multi-Pole Filters Functioning in the Submillimetric Wave Region at 150 GHz

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 fourpole 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.

Design of Microstrip Lossy Filters for Receivers in Satellite Transponders

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.

Wideband Lithium Niobate FBAR Filters

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.

Compact Ku band filter based on BMT dielectric resonators made in a single part using 3D ceramic stereolithography process

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 (εr = 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.

Multimaterial inkjet technology for the fabrication of multilayer components

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.

Compact diplexers and triplexers implemented with dual-mode cavities

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.

A dual-mode high-Q tunable filter reconfigured by cavity rotation

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.

Design of a compact hybrid filter using microstrip resonators and surface mounted cavities

A novel hybrid filter design based on low-Q microstrip resonators and high-Q surface mounted cavities is presented. The proposed structure is composed of quarter-wavelength resonators coupled with metallic cavities, which include capacitive posts for reducing the footprint. A six-pole quasi-elliptic filter is designed regarding specifications for a C-band satellite equipment. The design is detailed and initial experimental results are given.

Optimized Synthesis of Self-Equalized Microwave Filters

In this paper, a new methodology for synthesizing self-equalized filters is introduced. The methodology consists of optimizing the polynomial transfer and reflection functions considering amplitude and phase constraints simultaneously. The algorithm gives access to a more general class of functions than generalized Chebyshev (also called quasi-elliptic) functions. Two self-equalized filters are designed using this new methodology, and their performances are compared to general Chebyshev filters in order to put into evidence the interest of the proposed optimization algorithm. The first design leads to reduced group-delay variations, and the second one leads to a simplification of the hardware, reducing the number of resonators.

Design of compact and innovative microwave filters and multiplexers for space applications

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.