Ltcc-based Ultra-wideband Millimeter Wave Transceiver Front-end

As an important constitute of millimeter-wave electronic war (EW) sytem, ultra-wideband millimeter-wave transceiver front-end with miniaturization, low-weight, high integration can be implemented by LTCC technology. Based on Time Division Channel (TDC) technology, it is the first time to study the chanllenging 18-40GHz transceiver front-end in LTCC technology in China. This thesis introduces the basic features and technological level of LTCC in China and focuses on the research of ultra-wideband millimeter-wave transceiver front-end and its key components.First of all, based on lumped parameter model of interconnection between LTCC layers and impedance match theory,a microstrip-to-stripline transision in X-band is developed and perfomes well. Insertion loss is less than 1.4dB and return loss is better than -10dB of the back-to-back structure. It could be used to solve the cross wiring problem in the front-end. Second, from design method of parallel line coupled filter and based on the advantage of multi-layer LTCC substrates, traditional structure is modified and two new millimeter-wave wideband filters have been realized. Insertion loss is lower than 3dB and 2dB respectively. Stopband rejection could reach 30dB and 40dB at 4GHz away from passband respectively. Third, theory of three-line coupled filter is introduced. Insertion loss of the fabricated filter is less than 2dB and stopband rejection could reach 30dB at 4GHz away from passband. Last, based on coupling coefficient and external Qe value design theory, a full X-band band-pass filter is also achieved by using a new input and output coupled structure. Insertion loss is less than 1.5dB and it could be usd as IF filter. At the same time, based on Time Division Channel (TDC) theory, a millimeter-wave LTCC five channel switch-filter module with good stopband rejection is developed and insertion loss of the best channel is about 7.5dB.The whole ultra-wideband millimeter-wave transceiver front-end is fabricated in a ten-layer Dupont943 LTCC substrate. Dimension of the cavity is 108mm×80mm×18mm and its weight is lower than 220g. Test results show that receive gain at some frequency points is higher than 20dB and the smallest noise figure is about 7dB. Output power at some frequency points is higher than -5dB without the last power amplifier.