Broadband frequency recombination filter circuit with coupling function

Abstract

The invention discloses a broadband frequency recombination filter circuit with a coupling function. The broadband frequency recombination filter circuit mainly comprises an input port, an input matching part, a transmission line, an LC switch notch structure, a control line, an output matching part, an output port, a coupling line and a substrate. The LC switch notch structure is formed by connecting a capacitor, a switch and a grounding inductor in series, and the capacitors, the switch and the grounding inductor are connected to the transmission line in parallel at the interval of 1 / 4 working wavelength. Frequency recombination is achieved by controlling whether the LC switch notch structure is merged into the transmission line or not, and therefore the function of harmonic suppression in the passband of the broadband device is achieved. The filter has the characteristics of low loss, high stop-band suppression degree, capability of coupling reference signals, small size, easiness in integration with a power amplifier chip and the like, and is worthy of being popularized in the industry.

Description

Technical field: [0001] The present invention belongs to the technical field of microwave integrated circuits, and is a filter circuit, which is specifically a broadband frequency recombination filtering circuit with coupling function. Background technique: [0002] With the integration of microwave devices, generalization, miniaturization, broadband transceiver system coverage frequency reaches several times. The end microwave solid-state power amplifier at the end of the transmit circuitry has a variety of harmonic frequencies when operating, and if the device itself is too large, it is too effective to effectively inhibition. For transmitting components covering 2-6 GHz, 6-18 GHz, the second harmonic wave of some low-end frequencies fall within the passband (such as the second harmonic 16GHz of the 8GHz signal is still in the passband), fixed The filter circuit of the frequency will inevitably filter out the required frequency signal while filtering out the second harmonic. Th...

AI Technical Summary

Problems solved by technology

The disadvantages of this structure are: 1. With pure open-circuit stub resonance, the required stub is very long, longer when the frequency is low (it will be difficult to accept when the frequency is lower than 2G), and two groups need to be connected in series, Q value The low-side frequency roll-off characteristics are poor; 2. Two switches are connected in series on each resonant structure, and the insertion loss introduced is large; 3. The ports are not matched, and the standing wave will deteriorate sharply when the function is switched.

Images