Abstract: A compact bandpass filter within a multilayered low temperature co-fired ceramic (LTCC) substrate is provided. Each resonator comprises an inductor and a capacitor connected in parallel. A top ceramic substrate comprises a top conductive plate to form a first RF ground plane. A bottom ceramic substrate comprises a bottom conductive plate to form a second RF ground plane. A first ceramic substrate is between the top and bottom ceramic substrates. All inductors of the resonators are serpentine conductive traces on the first ceramic substrate. A second ceramic substrate is between the first and bottom ceramic substrates, having a plurality of conductive plates to form a plurality of capacitors that transmit RF signal from an input node of the bandpass filter to an output node of the bandpass filter. The resonators are located between the too and bottom conductive plates.

Abstract: A polarizer includes a waveguide, a pair of ridges and a dielectric slab. The waveguide has a side wall. The ridges protrude from the inner surface of the side wall of the waveguide, and the ridges are substantially symmetric with respect to the central axis of the waveguide. The dielectric slab is positioned in the waveguide, and the dielectric slab is fastened by the pair of ridges.

Abstract: A compact bandpass filter within a multilayered low temperature co-fired ceramic (LTCC) substrate is provided. Each resonator comprises an inductor and a capacitor connected in parallel. A top ceramic substrate comprises a top conductive plate to form a first RF ground plane. A bottom ceramic substrate comprises a bottom conductive plate to form a second RF ground plane. A first ceramic substrate is between the top and bottom ceramic substrates. All inductors of the resonators are serpentine conductive traces on the first ceramic substrate. A second ceramic substrate is between the first and bottom ceramic substrates, having a plurality of conductive plates to form a plurality of capacitors that transmit RF signal from an input node of the bandpass filter to an output node of the bandpass filter. The resonators are located between the too and bottom conductive plates.

Abstract: The present invention provides a balanced input/output filter device comprising two resonators, a pair of coupling capacitors, a positive input terminal and a negative input terminal, and a positive output terminal and a negative output terminal. Both sides of one resonator are serial connected to spiral-type inductors on the other metal layers, and both sides of the other resonator are serial connected to parallel-type capacitors on the other metal to layers. The coupling capacitors couple between the spiral-type inductors and the parallel-type capacitors respectively, and the output and input terminals are coupled to the spiral-type inductors and parallel-type capacitors respectively, which are coupled to the resonators.

Abstract: The present invention provides a balanced input/output filter device comprising two oscillators, a pair of coupling capacitors, a positive input terminal and a negative input terminal, and a positive output terminal and a negative output terminal. Both sides of one oscillator are serial connected to spiral-type inductors on the other metal layers, and both sides of the other oscillator are serial connected to parallel-type capacitors on the other metal layers. The coupling capacitors couple between the spiral-type inductors and the parallel-type capacitors respectively, and the output and input terminals are coupled to the spiral-type inductors and parallel-type capacitors respectively, which are coupled to the oscillators.