Joaquin Vague

Substrate Integrated Waveguide Diplexer Based on Circular Triplet Combline Filters

The design of substrate integrated waveguide (SIW) diplexers, based on combline triplet sections with transmission zeros (TZs) placed below and above the passband, is presented. In order to control the location of the TZs, positive and negative couplings are conveniently provided. A highly compact implementation based on circular substrate integrated coaxial resonators is proposed. An X-band diplexer with channel center frequencies at 9.5 and 10.5 GHz and absolute bandwidths of 400 MHz is designed. The structure shows important advantages in terms of size reduction, while keeping good insertion losses as well as high rejection and isolation levels.

Novel Planar and Waveguide Implementations of Impedance Matching Networks Based on Tapered Lines Using Generalized Superellipses

For the practical implementation of RF and microwave impedance matching networks, a widely employed solution—alternative to the use of classical impedance transformers—is based on tapered lines. This paper shows a simple method to design smooth tapers that take into account the dispersion of the line and the required design bandwidth simultaneously. A planar taper has been designed in microstrip technology with the same length of classical ones but improving their performances. A waveguide prototype has also been designed with similar performance to a commercial one but with one third of its length. Both tapered structures have been obtained through the optimization of very few parameters using the same design strategy. As a result, the reflection coefficient of the tapers can be optimally adapted to a given specific mask using the prescribed value of physical length. Experimental results for both tapers are included for the validation of the proposed topologies and the related design method.

New design methodology for multiband waveguide filters based on multiplexing techniques

This paper introduces a new design methododology for multiband waveguide filters based on a manifold approach. The new design algorithm is based on a subtle modification of the well-known multiplexer design algorithm. Transmission zeros, enhancing the overall performance, are also shown to be naturally produced. In addition to theory, the measured performance of a multiband filter is shown indicating very good agreement with the simulated response, thereby fully validating the new design methodology.

New design method of impedance matching networks based on tapered lines using generalized superellipses

One method used for designing RF and microwave impedance matching networks is based on tapered lines. This paper shows a simple method to design smooth tapers that take into account the dispersion of the line and the required design bandwidth simultaneously. The taper is designed through optimization of very few parameters. As a result, the reflection coefficient of the taper can be optimally adapted to a given specific mask using the prescribed value of physical length. Experimental results are included for validation of the proposed design method.

Exploring the tunability range of classic circular waveguide dual mode filters using EM-Based CAD

The objective of this paper is to use EM-Based CAD tools to investigate the maximum tunability range of classic dual mode filters in circular waveguide. In addition to simulations, measurements are also presented indicating very good agreement with theory, thereby fully validating the results obtained.