Substrate Integrated Waveguide Dual-mode Filter Research Articles

X‐band low‐phase noise oscillator employing substrate integrated waveguide dual‐mode filter

A novel low-phase noise oscillator employing a substrate integrated waveguide (SIW) dual-mode bandpass filter as a frequency stabilisation element within its feedback loop is proposed. The SIW dual-mode filter is implemented based on the use of the two degenerate modes (TE102 and TE201) and has a larger group delay peak than the conventional SIW cavity resonator. By taking advantage of the large group delay peak, the phase noise of the oscillator has significant improvement. An X-band oscillator with a GaAs HEMT packaged transistor has been designed and measured. At an oscillation frequency of 9.04 GHz, the measured phase noise is −111.9 dBc/Hz at 100 kHz offset. The output power is 6.1 dBm and the figure of merit is −198 dBc/Hz.

Diagnosis of lossy resonator filters with source-Load coupling using Y -parameters

This article presents a novel approach to extract the coupling matrix CM of a lossy cross-coupled resonator bandpass filter with source-load coupling using admittance parameters also known as Y-parameters. The Y-parameters are calculated by characteristic polynomials corresponding to the measured S-parameters. The unloaded quality factor of resonators and the CM can be extracted from the Y-parameters. The method allows one to diagnose a filter with source-load coupling without necessity of dealing with the degenerate poles problem of the Y-parameters and the measurement noise. The proposed diagnosis method can be used in a filter tuning and speeds up its physical realization. The method is verified by a fabricated fourth-order bandpass filter and a simulated substrate integrated waveguide dual-mode filter with source-load couplings. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:713-717, 2014.

Substrate integrated waveguide dual-mode filter using slot lines perturbation

A novel substrate integrated waveguide (SIW) dual-mode filter is proposed. By using an orthogonal input and output feed line, and two slot lines for disturbing two degenerate modes, two transmission zeros are created. A SIW dual-mode filter with centre frequency of 14.42 GHz was fabricated and measured, in which bandwidth is 380 MHz. Measured results show good agreement with simulated results.

An Novel Substrate Integrated Waveguide Square Cavity Dual-Mode Filter

In this pater, a novel substrate-integrated waveguide (SIW) square cavity dual-mode filter is proposed. By using an orthogonal input and output feed-line and two tuning metal vias for disturbing two degenerate modes, a transmission zero is derived. A SIW dual-mode filter with the center frequency of 14.7 GHz was fabricated and measured, in which fractional bandwidth is 3.8%. The measured results show good agreement with the simulated ones and validate the structures of the dual-mode filters.

Novel Dual-Mode Bandpass Filter with Transmission Zeros using Substrate Integrated Waveguide Cavity

A novel bandpass filter with two dual-mode cavities based on the substrate integrated waveguide (SIW) is presented. By making use of the inductive discontinuities in an SIW cavity, two degenerate modes can be excited. Due to the phase difference of the two modes in each cavity, two transmission zeros on each side of the passband are created, so the out-of-band rejection of the filter is significantly improved. An SIW dual-mode filter with a center frequency of 12 GHz has been fabricated and measured. The experimental results agree well with the simulation results.