Sheng-Lei Xiao

Design and implementation of an LTCC filter with high stopband rejection

A miniaturized and high stopband rejection bandpass filter(BPF) with three finite transmission zeros is presented in this paper. The BPF with a central frequency of 3.4 GHz and 200 MHz bandwidth is implemented in a novel distributed stripline configuration using LTCC (low-temperature-cofired ceramic) technology. A distinct feature of this filter is excellent out-of-band attenuation performance. The lower skirt of the passband is very steep. There is 36.5dB attenuation at 3.2 GHz, the input/output VSWR is less than 1.4. We employ Z-shape layer to produce the lower 2 transmission zeros. By properly controlling the cross-coupling between the second and the fourth resonator, transmission zero in higher skirt of the passband will be generated. Measurement results of mass production are shown to match well with the electromagnetic simulation, which validate the proposed structure. The overall size of the filter is 4.8mm×4.2mm×1.5 mm.

A miniaturized LTCC low-pass filter based on the lumped circuit model

In this paper, the design of miniaturized low-pass filter in a Low Temperature Co-fired Ceramic(LTCC) Technology is presented. The pass-band of the low-pass filter is from 900MHz to 1450MHz. The capacitor is constructed by multilayer MIM(Mental-Insulator-Mental) capacitor, and the inductor is fabricated by a narrow metal transmission line. The VSWR of input and output port is less than 1.6. The whole volume of final three-dimension model is 2.0mm×1.25mm× 0.90mm.

Design on antenna switch module for dual band phone (GSM/UMTS) using LTCC technology

This paper presents the results of an antenna switch module integrating a switch (SP9T) and two low-pass filters for harmonic rejection on a low temperature co-fired ceramic (LTCC) substrate. This contributes not only to reduce the size and weight, but also to shorten the development term of RF circuit and simplify the assembly process. It will be used for GSM/UMTS dual mode cellular phones. The 50-ohm in/out FEM utilized a GaAs PHEMT switch is attached to the LTCC substrate. S-parameter characterization of FEM demonstrated excellent insertion, return loss and isolation characteristics of ASM. The final three-dimension model occupied a volume of 4.5mm×3.2mm×1.4mm.

Design and implementation of an miniaturized LTCC filter with high stopband rejection

A miniaturized and high stopband rejection bandpass filter(BPF) with three finite transmission zeros is presented in this paper. The BPF with a central frequency of 3.2 GHz and 200 MHz bandwidth is implemented in a novel distributed stripline configuration using LTCC (low-temperature-cofired ceramic) technology. A distinct feature of this filter is excellent out-of-band attenuation performance. The lower skirt of the passband is very steep. There is 34.6dB attenuation at 3.0 GHz, the input/output VSWR is less than 1.4. We employ Z-shape layer to produce the lower 2 transmission zeros. By properly controlling the cross-coupling between the second and the fourth resonator, transmission zero in higher skirt of the passband will be generated. Measurement results of mass production are shown to match well with the electromagnetic simulation, which validate the proposed structure. The overall size of the filter is 4.8mm×4.2mm×1.5 mm.

A miniaturized wideband complementary LTCC diplexer based on transmission lines and lumped elements

This paper presented a design and simulation result of a miniaturized complementary diplexer realized by low-temperature co-fired ceramic (LTCC) technology. The diplexer consisted of two pass-bands, a central frequency of 1.175GHz with bandwidth of 46.8% and a central frequency of 1.925GHz with bandwidth of 28.6% respectively. In the presented structure, we used transmission lines to realize the characteristics of lower pass-band, while lumped circular inductors were adopted to achieve the requirements of upper pass-band. The interaction of the two filters was handled very well by using a complementary schematic. We managed to make the VSWR on the antenna port less than 1.7. The final three-dimensional model occupied a volume of 3.2×2.5×1.95-mm.

A UHF-band miniaturized LTCC band-pass filter with high performance

This letter outlines the design and manufacture of a UHF-band miniaturized band-pass filter realized by low-temperature cofired ceramic (LTCC) technology for super heterodyne microwave receiver applications. A distinct feature of this filter is the smaller size than conventional filter at such a low frequency and steady pass-band temperature electrical performance compared with surface acoustic wave filter. The band-pass filter with a central frequency of 750 MHz and a 40MHz pass-band is designed as a three-dimensional (3-D) structure based on distributed components. This filter has excellent out-of-band attenuation performance and it has 50.1 dB and 56.8 dB of attenuation at 550MHz and 950MHz respectively. The measured insertion loss is less than 2.7 dB at 750MHz, and the input/output VSWR is less than 2.0. The overall size of the miniaturized filter is only 4.5mm×3.2mm×1.5mm.