Coupled Resonant Filter and Its Debugging Method

Abstract

The invention discloses a coupled resonant filter and a debugging method thereof, comprising a resonant rod, a coaxial transmission line, a metal diaphragm and an outer conductor of the filter, the resonant rod is located in the outer conductor of the filter, and the two ends of the coaxial transmission line respectively pass through the filter The outer conductor and the two ends of the coaxial transmission line are respectively movably connected to the outer conductor of the filter; the two ends of the coaxial transmission line are respectively connected with a metal diaphragm, and the metal diaphragm is facing the resonant rod; In some cases, the distance between the cross-coupled metal diaphragm and the resonant rod is adjusted by pulling the coaxial transmission line, thereby adjusting the coupling size, which is a good solution to the problem that the cross-coupling structure filter in the traditional cavity can only be adjusted by opening the filter shell. The problem of difficult debugging brought about by the cross-coupling structure can achieve the technical effect of balancing multiple indicators at the same time.

Description

technical field [0001] The invention relates to the field of filters in the field of microwave passive circuits, in particular to a coupling resonant filter and a debugging method thereof. Background technique [0002] The function of the filter is to pass the signal of a specific frequency and attenuate the signal outside the frequency. The performance requirements of some filters are: small size, high out-of-band rejection, low insertion loss, low voltage standing wave ratio, high power and other multi-index balance and optimal realization. The traditional method is to realize by increasing the number of resonant cavities, adopting LC lumped filter structure or cross-coupling structure. [0003] However, traditional solutions are often only solutions for individual performance requirements. For example, in the prior art, the improvement of out-of-band rejection is achieved by increasing the number of resonant cavities. On the one hand, increasing the number of resonant ca...

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Problems solved by technology

[0003] However, traditional solutions are often only solutions for individual performance requirements. For example, in the prior art, the improvement of out-of-band rejection is achieved by increasing the number of resonant cavities. On the one hand, increasing the number of resonant cavities will increase The volume and weight of the filter; on the other hand, the increase of the resonant cavity leads to an increase in the number of tuning rods, which makes simulation and debugging more difficult and prolongs the design and debugging cycle

Another way to improve the out-of-band rejection is to use an intra-cavity cross-coupling structure, that is, to connect two non-adjacent resonant cavities with conductors inside the filter for proper coupling, which brings problems and makes debugging difficult, and the steps are cumbersome. The performance curve cannot be presented on the network analyzer in real time; at the same time, the cavities that use the cross-coupling need to be folded, so that the cavities that are not adjacent in space become adjacent in space, which increases the processing difficulty; in the prior art , the traditional method of reducing the size of the filter is to use the LC lumped filter structure, which brings at least three problems: small power capacity, poor insertion loss, and difficulty in mass production

[0004] That is to say, the existing filter has the problem of not being able to achieve the balance of multiple indicators

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