No abstract

No abstract

Abstract-This paper proposes a new compact filtering building block. It consists of two via holes embedded into a substrate integrated waveguide (SIW) cavity connected to capacitive metal patches at the top layer. This topology provides two coaxial modes performing a doublet filtering configuration. The proposed dualmode SIW coaxial cavity is studied in detail and guidelines for the filter design are given. As will be shown, the proposed building block presents a high degree of design flexibility, which allows for the design of multiple kind of bandpass filter responses, including both narrow-and wide-band bandpass filters along with TZ generation. As a verification, several filters are designed and implemented at 8 GHz.Index Terms-bandpass filter (BPF), coaxial line, dual-mode, substrate integrated waveguide (SIW), transmission zero.

Abstract-In this paper, combline substrate integrated waveguide (SIW) filters using electric and magnetic couplings are thoroughly studied. Thus, a negative coupling scheme consisting on an open-ended coplanar probe is proposed and analyzed in detail. Several in-line 3−pole filters at C-band are designed, manufactured and measured showing how the presented approach can be used for implementing direct couplings while enabling an important size reduction and improved spurious-free band compared to conventional magnetic irises. A fully-packaged quasi-elliptic 4−pole filter is also designed at 5.75 GHz showing how the negative coupling structure can be used for introducing transmission zeros by means of cross-couplings between nonadjacent resonators. Finally, average and peak power handling capabilities of these filters have been also analyzed from a multiphysics point of view. Measured results validate the theoretical predictions confirming that combline SIW filters can handle significant levels of continuous and peak power, providing at the same time easy integration, compact size and advanced filtering responses.Index Terms-Cross-coupled filters, electric and magnetic mixed couplings, multiphysics analysis, power handling capabilities, quasi-elliptic filter, substrate integrated waveguide.

No abstract

In this work, the power handling capability of microstrip filters is studied in detail. This study is addressed from two perspectives, depending on the physical phenomenon limiting the maximum power that the microstrip filter can handle. One of these phenomena is air breakdown or corona effect, which is linked to the peak power handling capability (PPHC) of the device, and the other is the self-heating, which limits the device average power handling capability (APHC). The analysis is focused on three kinds of filtering topologies widely used both in academia and industry, such as the coupled-line, stepped impedance resonator and the dual-behaviour resonator based filters. Closed-form expressions are computed to predict both the PPHC and the APHC as a function of the geometrical parameters of the resonators integrating the filter. Guidelines are also given to extrapolate the provided computations to other filtering topologies based on other kinds of resonators. To validate this research study, three bandpass filters centered at 5 GHz have been implemented and fully characterized by means of two measurements campaigns which have been carried out, one for the PPHC and another one for the APHC. The measured results have validated the performed study and corroborated the conclusions obtained throughout the paper. Index Terms-Average power handling capability (APHC), coupled-line filter, electro-thermal analysis, microstrip filter, peak power handling capability (PPHC), power applications, stepped impedance resonator (SIR).

No abstract

An original and simple approach to design electronically reconfigurable‐bandwidth microwave planar bandpass filters is reported. It exploits the use of transversal signal‐interference filtering sections shaped by a branch‐line directional coupler arranged in reflection mode with switchable stubs. Thus, by switching on/off these stubs through p–i–n diodes, sharp‐rejection filtering functions with different bandwidths and multiple out‐of‐band transmission zeros are produced. Analytical equations and guidelines for the synthesis of the basic switchable filter building block are detailed. Moreover, a 2 GHz two‐stage proof‐of‐concept microstrip prototype, with five distinct bandwidth states ranging from ∼10 to 50%, is built and characterised for experimental verification.