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The objective of this article is to describe a new family of microwave bandpass filters in the rectangular waveguide based on resonant apertures, which can be used to implement both single- and dual-band transfer functions. The use of capacitive stubs and a staircase configuration is also discussed in order to enhance the out-of-band response and the selectivity of the filter with respect to the state of the art. Finally, simulations are compared with measured results, showing very good agreement, thereby fully validating both the new filter topologies and the design procedure. [ABSTRACT FROM AUTHOR]

This paper studies the corona discharge power thresholds in microstrip bandpass filters (BPFs) and, in particular, is focused on a solution based on λ/2 cover-ended resonators to enhance their peak power handling capability (PPHC). First, a parametric analysis is carried out to evaluate the variation of the maximum electric field and the unloaded quality factor (Qu) as a function of the cover's geometrical dimensions (i.e. height, length, and width). Next, several microstrip BPFs centered at 1.6 GHz are designed, and their behaviors under moderate-to-high applied RF power signals are simulated to corroborate the previous study. A suitable number and size of covers are selected to enhance PPHC without barely degrading the filters' electrical performance and, consequently, without hardly increasing the insertion losses. Finally, two third-order filters with covers and without covers (benchmark prototype) are manufactured, by way of illustration, and they are tested in the European High-Power RF Space Laboratory to validate the good performance of the proposed solution, where a PPHC enhancement of 3.1 dB at high pressures is achieved as compared to the benchmark prototype. [ABSTRACT FROM AUTHOR]

The objective of this article is to describe the design of a new family of wideband filters in a rectangular waveguide based on hybrid couplings and a staircase configuration. The use of E-plane T-junctions and E-plane folded structures is also discussed, in order to enhance the out-of-band response and the selectivity of the filter with respect to the current state of the art. The design of several hybrid filter prototypes is discussed in detail, including manufacturing sensitivity and high-power analysis. Finally, simulations and measurements for an eight-pole filter prototype are also compared, showing very good agreement, thereby fully validating both the design procedure and the new filter topology that we propose. [ABSTRACT FROM AUTHOR]

In this article, we describe several alternative inline implementations for combline filters with transmission zeros (TZs) located both below and above the passband. A systematic design procedure is also presented using a lumped-element equivalent circuit. Following the design procedure that we propose, up to $N+1$ TZs can be implemented with an inline filter of order $N$. The generation of the TZs is explained physically in terms of mixed inductive and capacitive couplings. Several filters are also manufactured and tested. Good agreement between the measured and simulated results is demonstrated, thereby fully validating the new filter concepts. [ABSTRACT FROM AUTHOR]

This work describes a new strategy for improving the peak power handling capability (PPHC) of microstrip bandpass filters (BPFs) without any degradation in the electrical performance. For this purpose, a new resonator topology with rounded open-circuit terminations is proposed. Using this strategy, sharp edges are avoided, and a reduction of the maximum peak voltage (Vpeak) is obtained, leading to higher peak power thresholds. An in-depth analysis of the variation of Vpeak and PPHC as a function of the circle radius is also carried out. As a validation, two microstrip BPFs centered at 1.6 GHz with different end-circle sizes are designed, manufactured, and measured, showing a PPHC enhancement of 2.10 and 1.15 dB, respectively, compared to a standard microstrip BPF. [ABSTRACT FROM AUTHOR]

In this article, we present a novel bandpass filter based on dual-mode resonators. The dual-mode operation is based on integrated coaxial and rectangular waveguide cavities. Furthermore, we also discuss a systematic design procedure for the selection of the dimensions of the various constituent elements of the filter, which is based on the well-known aggressive space mapping technique. The design of a five-pole bandpass filter operating in the X-band is discussed in detail, including the measured data. The comparison between simulations and measurement shows very good agreement, thereby fully validating both the new filter structure and the design procedure. [ABSTRACT FROM AUTHOR]

In this article, we describe a new family of multiband waveguide filters based on a folded topology. The folded topology allows to use the filters of different orders and the introduction of transmission zeros. The design of the multiband filter is based on the aggressive space mapping (ASM) technique and is able to take into account manufacturing details, such as round corners and tuning elements. The filter structure is validated by designing, manufacturing, and measuring a triband filter. The agreement between simulations and measurements is shown to be excellent, thereby fully validating both the filter topology and the design process. [ABSTRACT FROM AUTHOR]

This article describes the design procedure of a compact wideband waveguide filter, based on stepped impedance resonators (SIRs) and a combined usage of capacitive and inductive coupling irises, that provides a significant improvement in the out-of-band response of the filter with respect to the state-of-the-art. In addition to theory, several filter prototypes have been designed and manufactured. A detailed sensitivity analysis has also been carried out. Finally, simulations and measurements are compared, showing very good agreement, thereby fully validating the new filter topology. [ABSTRACT FROM AUTHOR]

In this paper, the design of a novel planar narrowband microstrip filter is presented. The structure is designed and manufactured in microstrip technology, and it is formed by set of pairs of resonators of different lengths. The length of one resonator in each pair is adjusted so that a suitable odd resonance is tuned to the center frequency of the filter. The length of the other resonator is adjusted so that the next even resonance is tuned again to the center frequency of the filter. The different path of the signal in each resonator produces a cancellation of energy at a given frequency, therefore implementing a transmission zero in the insertion-loss response of the filter. First, this paper presents a design example of a single set of resonators (basic unit cell) working at the fifth and sixth resonances. Then, two basic unit cells working at the first and second resonances are first optimized, and then they are cascaded to show how higher-order filter responses can be implemented. The measured results confirm the theoretical predictions, and validate the new structures for high-selectivity applications. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 450–455, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20499 [ABSTRACT FROM AUTHOR]