Gallium arsenide dual-mode bandpass filter and its preparation method

Abstract

The invention provides a gallium arsenide dual-mode band-pass filter and a manufacturing method of the gallium arsenide dual-mode band-pass filter. According to the filter, the requirement for a miniaturized millimeter-wave circuit is met, the insertion loss is small, and the selectivity is high. According to the technical scheme, a loading branch and a lambda / 2 resonator constitute a bent branch line loading type dual-mode resonator of an annular structure; microwave signals fed through an input micro-strip are transmitted to an output micro-strip through two physical channels of the filter, so that frequency selection of a pass band is achieved, wherein according to one channel, the signals are transmitted through an input coupling branch and an output coupling branch, an extra out-of-band transmission zero is provided, and the position of the zero is adjusted through the lengths and the coupling distances of the input coupling branch and the output coupling branch, and according to the other channel, the microwave signals are coupled to the dual-mode resonator through an incoming feeder and then are coupled to the output micro-strip through the dual-mode resonator, two transmission pole pass bands and two transmission zero stop bands are formed by the dual-mode resonator, and one of the transmission pole pass bands and one of the transmission zero stop bands are provided by a dual module of the dual-mode resonator.

Description

technical field [0001] The invention relates to a filter applied to microwave and millimeter wave circuits, in particular to a miniaturized, low-loss, high-selectivity dual-mode bandpass filter chip based on thin film technology and gallium arsenide substrate. Background technique [0002] Filters are key passive devices in radio communication systems, and microwave bandpass filters are one of the most important types, which have been widely studied and applied, such as cavity filters, microstrip parallel-coupled bandpass filters, hairpin filters, etc. type filter etc. Microwave wireless communication has experienced more than half a century of development, and the use and development of frequency resources has continued to deepen and become more and more tense. Therefore, in recent years, a hot research direction has emerged in the field of communication, that is, ultra-narrowband communication. It can transmit information at a very high rate on a very narrow bandwidth, th...

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Problems solved by technology

Since then, a variety of dual-mode filters with different structures have been designed, including square, circular, triangular and other chip types and different forms of ring structures; mainly closed structures corresponding to wolff theory, and chip and ring structures, etc. The structure is often used in the design of high-efficiency antennas. In theory, this type of filter has a large radiation loss; while the double-mode resonator structure based on branch line loading (Tu, W.H., “Compact double-mode cross-coupled microstrip bandpass filter with tunable transmissionzeros,"IET Micro.Antennas Propag.,Vol.2,No.4,373-377,2007.) It is easy to analyze even and odd modes, and the transmission zero is easy to control, which has attracted wide attention (such as Figure 4 ); however, the above-mentioned dual-mode filter is mostly used at frequencies below 10GHz, because the dual-mode filter requires a strong coupling between the feeder and the resonator, so the required coupling gap is small ( Figure 4 shown in 15 and 16), often below 50 μm, and the photolithography technology cannot satisfy such a narrow coupling gap, and as the frequency increases, the resonator ( Figure 4 Shown in 11~13) becomes smaller, the coupling gap length ( Figure 4 The lengths of 11 and 12 in the middle) are shortened, and the coupling length will be further shortened, and a narrower coupling gap is required, which is impossible for the current lithography technology precision; therefore, it is urgent to develop a small Chip filter for spaceborne phased array T / R module application

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