Compact ridged waveguide filters with improved stopband performance

A novel ridged waveguide bandpass filter configuration is proposed. The proposed filter has comparable size to standard E-plane filters while having suppressed spurious resonance. Compactness is achieved by taking advantage of the properties of slow waves in half wavelength resonators, while spurious behaviour suppression is achieved by means of an integrated lowpass structure. Periodicity is readily imposed by cascading ridge waveguides with rectangular waveguides. The structure is simple and compatible with E-plane technology. Numerical and experimental results are presented to validate the argument

Ridged waveguide manifold multiplexers with improved performance

This paper demonstrates the bandwidth improvement of a multiplexer overcoming the limitations imposed by the poor stopband performance of standard waveguide E-plane filters. Bandwidth improvement is achieved by introducing an integrated compact ridge waveguide filter in the multiplexer. A four-channel X-band ridged waveguide manifold multiplexer is used as an example. Electromagnetic modelling of the multiplexer and experimental verification of an integrated ridge waveguide filter are presented

A 3rd order ridge waveguide filter with parallel coupled resonators

A 3rd order novel compact E-plane ridge waveguide filter is presented. Miniaturization of 2:1 is achieved upon introducing a configuration of parallel coupled E-plane ridge waveguide resonators. The presented filter allows for a transmission zero at finite frequencies to address sharp cutoff specifications. Furthermore it maintains the fabrication simplicity and mass-producibility of standard E-plane filters. Numerical and experimental results are presented to validate the presented configuration

Simple tuning procedure for coupled-resonator filters

A new method for the initial design of direct-coupled cascaded resonators waveguide filters is proposed. The method is based on tuning the resonant frequency of cascaded resonators separately and is equally valid for the uniform and non-uniform case. The initial values obtained are in many cases a better approximation than equivalent K-inverter resonator prototypes, and the whole design procedure requires significantly less computational effort. Furthermore the method can predict the stopband performance of the filter from the harmonic behaviour of its resonators. Numerical and experimental results in the case of E-plane filters demonstrate the validit

Experimental investigation of open-ended microwave oven assisted encapsulation process

An open ended microwave oven is presented with improved uniform heating, heating rates and power conversion efficiency. This next generation oven produces more uniform EM fields in the evanescent region forming part of the heating area of the oven. These fields are vital for the rapid and uniform heating of various electromagnetically lossy materials. A fibre optic temperature sensor and an IR pyrometer are used to measure in situ and in real-time the temperature of the curing materials. An automatic computer controlled closed feedback loop measures the temperature in the curing material and drives the microwave components to obtain predetermined curing temperature cycles for efficient curing. Uniform curing of the lossy encapsulants is achieved with this oven with typical cure cycle of 270 seconds with a ramp rate of 1oC/s and a hold period of 2 minutes. Differential scanning calorimeter based measurement for the pulsed microwave based curing of the polymer dielectric indicates a ~ 100% degree of cure

CAD of RF and microwave filters for wireless communications

This paper presents the CAD of RF and microwave filters such as lumped element, combline and waveguide bandpass filters for wireless communication systems. A new high-Q periodic resonator has been used for combline filter applications. A significantly higher Q factor than that for a conventional combline resonator in the same volume has been achieved