Qunfei Han

A LTCC miniaturized broadband modified Marchand balun

A miniaturized broadband marchand balun using low temperature co-fired ceramic (LTCC) technology is proposed in this paper. Modified Marchand balun has been chosen to broaden the bandwidth, and it covers the band of 0.95-2.15 GHz. A spiral broadside coupled stripline is adopted to realize the proposed miniaturized balun, and the overall size of the LTCC balun is only 2.0mm×1.25mm×0.95mm. Measured results match well with the computer simulation. The fabricated balun with symmetric structure achieves good VSWR and insertion loss performance, as well as excellent amplitude imbalance and phase difference.

Miniaturized LTCC wideband bandpass filter using lumped-element shunt LC resonators

In this letter, shunt LC resonators realized by multilayer spiral inductors and Metal-Insulator-Metal (MIM) capacitors in parallel connection are proposed to design the wideband bandpass filter (BPF) using Low Temperature Co-fired Ceramic (LTCC) technology. A distinct feature of this filter is the ingenious use of mutual coupling and broadside coupling which are introduced by the close packed elements, so as to achieve the coupling between adjacent resonators. With the assistance of the cross coupling which is implemented by a Z-shaped metal layer, a pair of transmission zeros are produced both above and below the passband.

Research on a novel 2∼18 GHz PHEMT MMIC digital attenuator with low insertion phase shift

A novel ultra broadband (2 ~ 18 GHz) 6-bit monolithic microwave integrated circuit(MMIC) digital attenuator with low insertion phase shift is presented. Phase compensation techniques were used in the MMIC design to reduce the insertion phase shift when the attenuation state varies. Performance redundancy optimization strategy was used to get the best performance. This attenuator is fabricated with 0.5μm GaAs PHEMT process. On-wafer measurement results of the developed MMIC chips in the 2-18-GHz band show that the 6-bit MMIC digital attenuator has 0.5 dB resolution and 31.5 dB dynamic attenuation range, input and output VSWR<; 1.8 for all attenuation states, and attenuation accuracy: +2.31dB/-0.51dB; insertion phase shift: +6.28°/-1.53° referenced insertion loss: <;-5.71dB; the chip size is 2.89mm×1.22mm×0.1mm. To ensure high yield, Performance redundancy optimization strategy is used in design, and PCM (Process Control Map) and SPC(Statistics Process Control) technology are used in fabrication. The yield is more than 85%.

A novel miniaturized wideband bandpass filter using LTCC technology

A new method for implementing the wideband bandpass filter utilizing low temperature co-fired ceramic(LTCC) multilayered technology has been proposed. The circuit of this filter is composed of 9-order resonators by inductance coupling. Based on the improved structure of the tapped combline filter, combined with circuit simulation and 3D EM simulation, a wideband filter with the bandwidth from 4GHz to 11GHz is realized with the help of DOE. The fractional bandwidth is more than 93.3%. The group delay is less than 0.6ns in the bandwidth. The implemented filter exhibits a good frequency response, low insertion loss, and especially very compact size. The final size of the fabricated filter is only 3.2mm×2.5mm×1.5mm.

6∼18 GHz GaAs PHEMT 6-bit MMIC digital phase shifter

A 6~18 GHz GaAs PHEMT monolithic microwave integrated circuit(MMIC) digital phase shifter is presented. Based on our special design of both the series Pseudomorphic High Electron Mobility Transistor (PHEMT) and shunt PHEMT control feeders, the MMIC possesses the feature of excellent return loss characteristic. Amplitude compensation techniques are used in the MMIC design to make sure high phase shift precision when the phase shift state varies. Performance redundancy optimization strategy is used to get the best performance. On-wafer measurement results of the developed MMIC chip in the 6-18-GHz band shows that the phase shift error is less than 5.625°±2°, 11.25°±2°, 22.5°±3°, 45°±4°, 90° ±7°, 180°±6.5°, the insertion loss is within the range of 8.6 dB~12.3 dB, input and output VSWR of 64 phase shift states is less than 2.1. The chip size is only 3.555 mm×4.055 mm×0.1 mm. To ensure high yield, Performance redundancy optimization strategy is used in design, and PCM (Process Control Map) and SPC(Statistics Process Control) technology are used in fabrication. The yield is more than 85%.

Miniaturized lumped element complementary RF LTCC diplexer

The proposed diplexer is composed of complementary bandpass filter and bandstop filter in parallel connection. In the presented 3D physical structure, lumped multilayer inductor and Metal-Insulator-Metal (MIM) capacitor are used to realize the circuit elements. The final structure is verified by 3D Electromagnetic (EM) simulator and good agreement is found between simulation and measurement. The size of the fabricated diplexer is 4.3mm×3.2mm×2.6mm.

A novel compact LTCC UWB bandpass filter using semi-lumped highpass filter

A new method for implementing the wide band bandpass filter utilizing low-temperature co-fired ceramic(LTCC) multilayered technology has been proposed. By using the optimum semi-lumped highpass filter structure, an ultra-wideband(UWB) filter with the operation frequency band from 3.1 GHz to 11.5 GHz is realized. The implemented filter exhibits a good frequency response, low insertion loss, suppressed spurious passband, and especially very compact size with simple structure. The final size of the fabricated filter is only 3.2mm×1.6mm×0.94mm.