Germán Torregrosa-Penalva

Compact Wideband Bandstop Filter With Four Transmission Zeros

This work presents a new type of compact wideband bandstop filter (BSF) with four transmission zeros in the stopband. The proposed filter topology consists of a coupled line directional coupler connected in parallel to an interference transmission line. The filter characteristics can be easily controlled by the coupling factor of the coupled line coupler and the characteristic admittances of both the coupler and the transmission line. Design equations and curves are provided for the filter design. To validate the proposed topology, a compact microstrip BSF centered at 2.0 GHz with a measured 20 dB rejection bandwidth of 100% and sharp rejection characteristics is designed and built.

Low-Pass and Bandpass Filters With Ultra-Broad Stopband Bandwidth Based on Directional Couplers

The design of planar sharp-rejection low-pass and bandpass filters (LPFs and BPFs) featuring a very broad stopband is addressed in this paper. For the LPF case, two new classes of bandstop signal-interference transversal filtering section (TFS) consisting of power directional couplers in reflection mode are proposed. In the BPF application, additional short-circuit stubs are inserted at the TFS input/output accesses. Based on these filtering cells, the devised LPF and BPF approaches are then derived from the cascade of multiple TFSs with frequency-contiguous stopbands. Thus, an overall attenuated band showing an ultra-large spectral width and deep rejection levels through the generation of several transmission zeros (TZs) is synthesized. Furthermore, such unprecedented filtering performances are obtained for much lower circuit complexity than available solutions. The operating principle of the conceived LPF and BPF topologies and guidelines for their realization are detailed. This includes formulas for their analytically designable TZs. For practical validation, three LPF prototypes and one wideband BPF circuit are also fabricated in microstrip technology and tested.

Multipactor Susceptibility Charts of a Parallel-Plate Dielectric-Loaded Waveguide

In this paper, we investigate the dependence of multipactor susceptibility charts of a parallel-plate dielectric-loaded waveguide on the different geometrical and electrical parameters of the waveguide under study. Susceptibility charts are obtained for different properties of the dielectric material loading the structure (i.e., different height, dielectric constant, and secondary emission yield (SEY) responses are considered). Realistic susceptibility charts are also computed employing experimental SEY measurements from different metallic and dielectric materials.

Low cost Ka band transmitter modules for LMDS equipment mass production

Two different Ka band medium power transmitters for LMDS (Local Multipoint Distribution System) applications have been designed proving successful performance while introducing low cost components and simple mounting techniques for industrial purposes. Commercially available BGA and LM packaged components are attached with epoxy dispensing procedures to a 0.254 mm height cost effective plastic substrate. The output power stages are die form MMIC amplifiers which are first mounted on separate carriers. A novel epoxy-on-bonding die attaching technique is used in order to prevent undesired bonding to plastic quality and performance. New active biasing networks are employed so that no later adjustment is necessary to control the overall transmitter behaviour. Active biasing also allows higher PAE than usual resistor dividers for gate biasing while preserving linearity and P1 dB output power. The transmitter modules work at 31.15 GHz and 25.7 GHz respectively. The measured P1 dB was 26.5 dBm and PAE at P1 dB was 16%.

Hybrid-ring-based signal-interference planar lowpass filters with ultra-broad stopband

A new approach of microwave planar quasi-elliptic-type lowpass filter (LPF) with ultra-wide stopband is presented. It makes use of an original class of bandstop transversal filtering section (TFS) based on a generalized version of the hybrid ring. This circuit configuration, operating under feedforward signal-combination principles, enables sharp-rejection lowpass transfer functions with multiple transmission zeros (TZs) to be generated. The flexibility of the devised bandstop TFS to control its electrical performances is verified. Also, two proof-of-concept multi-stage LPF microstrip prototypes are developed and measured. They are ideally designed to exhibit a 1-GHz-3-dB-cut-off-frequency passband with a minimum power matching level of 20 dB and a broad stopband for a power rejection capability higher than 20 and 40 dB, respectively.

Low Cost Millimeter Wave Transmitter Based on SMT Techniques

The aim of this paper is to present a millimeter wave transmitter (Ka band) designed to be manufactured using low cost, surface mountable millimeter wave components onto soft PTFE based substrates. The system employs recently developed millimeter wave monolithic integrated circuits (MMICs) packaged in surface mountable Ball Grid Arrays (BGA) for the low power subsystems and surface mountable Land Grid Arrays (LM packages) for the driving power stages, mainly the power amplifiers. Tailored active bias servos are also employed to improve efficiency and reliability and to reduce adjustments and manufacturing costs also. Output power compression point of P1dB = 26dBm and Power Added Efficiency PAE=18 % have been measured at 31 GHz.

Comments on “Novel Ultra-Wideband Bandpass Filter Using Shorted Coupled Lines and Transversal Transmission Line”

In this paper an ultra-wideband (UWB) band-pass filter (BPF) configuration consisting of a short-ended coupled-line coupler connected in parallel to a transmission line is presented.

Microwave Power FET DC Model Extraction through Isothermal Non-Pulsed Measurements

In this work a new approach to extract the experimental fitting parameters of a microwave power FET temperature dependent DC-model is presented. The suggested procedure avoids the possibility of multiple model solutions by eliminating the measurements temperature dependence. This is accomplished by making use of isothermal measurements which in turn are obtained following a simple non-pulsed approach. The proposed technique was applied to a commercial X band MMIC FET power amplifier