port and a high return loss at the input and output ports across the band of operation. Concerning the presented device, the insertion loss is less than 1 dB, whereas the return loss is better than 12 dB at the centre of the C-band as shown in Figure 4. There is a good agre ement between the measured and simulated results in Figures 3 and 4.There is another parameter that can be used to assess the performance of the phase shifter: it is the group delay [11]. To handle a narrow pulse operation or a high data rate transmission/ reception, the group delay of the device should show a low fluctuation around the mean value. The phase shifter presented in this article has almost a constant group delay (less than Ϯ0.05-ns peak fluctuation) across the C-band as depicted in the simulated results in Figure 5.
CONCLUSIONThe design of a broadband fixed phase shifter for C-band applications has been presented. The proposed device is composed of two parts: a quadrature 3-dB directional coupler and the Wilkinson combiner. The directional coupler utilized in the design is based on the edge-coupled microstrip lines. A slotted ground plane was used underneath the coupled lines to relax the required gap between the coupled lines and make the manufacturing process easy. The phase shifter presented in this article has shown a 45°Ϯ 5°fixed differential phase shift across the band 4 -8 GHz with less than 1-dB insertion loss and better than 12-dB return loss at the centre of the C-band. The designed device has also shown a flat group delay, which enables its use in a narrow pulse transmission/ reception and in the high data rate systems. The designed phase shifter has a compact size with dimensions of 30 mm ϫ 30 mm. 12. R. Collin, Foundations for microwave engineering, 2nd ed., IEEE Press, New York City, NY 2001. 13. H. Nishiyama and J. Nakazoe, Efficient calculation of interconnect capacitance and characteristic impedance for coupled pairs of microstrip-like transmission lines, IEICE Trans Electron Commun 80 (Part 2) (1997). ABSTRACT: The design of a rectangular cavity resonator implies to solve the Maxwell equations inside that cavity, respecting the boundary conditions. The resonance frequencies appear as conditions in the solutions of those equations. When a small piece of a magnetic material is introduced in the cavity, the resonance frequency and the quality factor changes. These effects can be used in the measurement of the permeability of the material. The relations are derived from the perturbation theory of resonant cavities and are simple when we consider only the first-order perturbation in the magnetic field caused by the sample. This is guaranteed when linearity exists between the measured perturbation and the volume of the inserted sample. In this work, a resonant cavity to measure the magnetic permeability of a material, at 2.16 GHz, was developed and characterized. ABSTRACT: In this article, a 34-GHz substrate integrated waveguide (SIW) quasi-elliptic filter fabricated in PCB is presented. The filter consists of one SIW...
