Non-reflection band-pass filter chip based on Lange bridge

Abstract

The invention provides a non-reflection band-pass filter chip based on a Lange bridge, which comprises a dielectric substrate and a non-reflection band-pass filter arranged on the dielectric substrate, and is characterized in that the non-reflection band-pass filter comprises a first Lange bridge, a second Lange bridge, a first band-pass filter, a second band-pass filter, a first absorption resistor and a second absorption resistor, one end of the first band-pass filter and one end of the second band-pass filter are respectively connected with one power division coupling port of the first Lange bridge in a one-to-one correspondence manner, and the other end of the first band-pass filter and the other end of the second band-pass filter are respectively connected with one power division coupling port of the second Lange bridge in a one-to-one correspondence manner; one of the remaining two ports of the first Lange bridge is used as a signal input port Port1, and the other port is grounded through a first absorption resistor; one of the remaining two ports of the second Lange bridge serves as a signal output port Port2, and the other port is grounded through a second absorption resistor. According to the invention, the advantage of large bandwidth of the Lange bridge is utilized, and wide out-of-band non-reflection bandwidth is realized.

Description

Technical Field

[0001] This invention belongs to the field of radio frequency and integrated circuit technology, specifically a reflection-free bandpass filter chip based on Lange bridge. Background Technology

[0002] Bandpass filters are widely used in microwave circuits to filter out out-of-band spurious signals and improve frequency selectivity. Conventional bandpass filters approach total reflection outside the band, which can affect the operating state of adjacent devices, causing increased intermodulation products, gain fluctuations, and other problems that impact system performance. Especially in mixing systems, ordinary bandpass filters can worsen mixing spurious signals, while using reflection-free bandpass filters can eliminate reflected signals at the mixer output, greatly improving spurious suppression.

[0003] Currently, common non-reflective bandpass filters are generally implemented in the form of microstrip or lumped LC circuits, which are large in size and not conducive to the miniaturization of circuit design. Summary of the Invention

[0004] This invention proposes a reflection-free bandpass filter chip based on Lange bridge to solve the problem of out-of-band reflection signals in bandpass filters, which degrades the performance of microwave systems.

[0005] The technical solution to achieve the objective of this invention is as follows: a reflection-free bandpass filter chip based on a Lange bridge, comprising: a dielectric substrate and a reflection-free bandpass filter disposed on the dielectric substrate. The reflection-free bandpass filter includes a first Lange bridge, a second Lange bridge, a first bandpass filter, a second bandpass filter, a first absorption resistor, and a second absorption resistor. One end of the first bandpass filter and the second bandpass filter are respectively connected to a power splitting coupling port of the first Lange bridge, and the other end of the first bandpass filter and the second bandpass filter are respectively connected to a power splitting coupling port of the second Lange bridge. The remaining two ports of the first Lange bridge are used as a signal input port (Port1) and grounded through the first absorption resistor. The remaining two ports of the second Lange bridge are used as a signal output port (Port2) and grounded through the second absorption resistor.

[0006] Compared with the prior art, the significant advantages of this invention are:

[0007] This invention utilizes the large bandwidth advantage of the Lange bridge to achieve a wide out-of-band reflection-free bandwidth. The Lange bridge in this invention can be rationally bent and laid out according to the size of the bandpass filter, making better use of chip area. The reflection-free bandpass filter chip based on the Lange bridge described in this invention can achieve good reflection-free characteristics within 120% of the relative bandwidth. This invention has the advantages of small size and wide reflection-free bandwidth.

[0008] The present invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0009] Figure 1 This is a block diagram illustrating the principle of the reflection-free bandpass filter chip based on the Lange bridge of this invention.

[0010] Figure 2 This is a schematic diagram of the chip structure according to a preferred embodiment of the present invention.

[0011] Figure 3 Performance curves of a reflection-free bandpass filter chip based on a Lange bridge provided in an embodiment of the present invention. Detailed Implementation

[0012] like Figure 1 , 2 As shown, a reflection-free bandpass filter chip based on a Lange bridge includes a dielectric substrate and a reflection-free bandpass filter disposed on the dielectric substrate. The reflection-free bandpass filter includes a first Lange bridge (Q1), a second Lange bridge (Q2), a first bandpass filter (F1), a second bandpass filter (F2), a first absorption resistor (R1), and a second absorption resistor (R2). One end of the first bandpass filter (F1) and the second bandpass filter (F2) are respectively connected to a power splitting coupling port of the first Lange bridge (Q1), and the other end of the first bandpass filter (F1) and the second bandpass filter (F2) are respectively connected to a power splitting coupling port of the second Lange bridge (Q2). One of the remaining two ports of the first Lange bridge (Q1) is used as a signal input / output terminal, and the other is grounded through the first absorption resistor (R1). One of the remaining two ports of the second Lange bridge (Q2) is used as a signal input / output terminal, and the other is grounded through the second absorption resistor (R2).

[0013] The input signal is divided by the first Lange bridge (Q1) and the second Lange bridge (Q2) and then enters the first bandpass filter (F1) and the second bandpass filter (F2). After reflection, the two signals that return to the input ports of the first Lange bridge (Q1) and the second Lange bridge (Q2) are ideally equal in amplitude and 180° out of phase, thus achieving the non-reflection characteristic of the chip port.

[0014] Furthermore, the non-reflective bandpass filter chip is based on a GaAs substrate and is implemented using an integrated passive device process, featuring small size and high integration.

[0015] Furthermore, the first Lange bridge (Q1) and the second Lange bridge (Q2) have the same structure and adopt a multi-bend winding method, which has the characteristics of small size and large bandwidth;

[0016] Furthermore, the first bandpass filter (F1) and the second bandpass filter (F2) have the same structure, adopting a fifth-order structure, consisting of two series resonators and three parallel resonators, and the parameters of the two filters are completely identical; the series resonators are connected in series in the circuit, and one end of the parallel resonators is connected in the circuit, while the other end is grounded;

[0017] Furthermore, the first bandpass filter (F1) includes a first inductor L1, a first capacitor C1, a second inductor L2, a second capacitor C2, a third inductor L3, a third capacitor C3, a fourth inductor L4, a fourth capacitor C4, a fifth inductor L5, and a fifth capacitor C5. The second inductor L2, the second capacitor C2, the fourth inductor L4, and the fourth capacitor C4 are connected in series. The first inductor L1 and the first capacitor C1 are connected in parallel, with one end grounded and the other end connected to the end of the second inductor L2 away from the second capacitor C2. The third inductor L3 and the third capacitor C3 are connected in parallel, with one end grounded and the other end connected to the junction of the second capacitor C2 and the fourth inductor L4. The fifth inductor L5 and the fifth capacitor C5 are connected in parallel and to the end of the fourth capacitor C4 away from the fourth inductor L4.

[0018] In an optional embodiment of the present invention, the dielectric substrate is made of GaAs material with a thickness of 100 μm and a dielectric constant of 12.9.

[0019] In an optional embodiment of the present invention, the first Lange bridge (Q1) and the second Lange bridge (Q2) are flexibly constructed using multiple bends and windings according to the shape of the bandpass filter to make full use of the chip area. Optimizing the line width and line spacing of the Lange bridge can increase the operating bandwidth.

[0020] In an optional embodiment of the present invention, a reflection-free bandpass filter operating in the X-band is designed. The components are integrated on a single chip using IPD technology, achieving the goal of high integration and small size. The size is only 2.3mm × 1.6mm × 0.1mm, which is suitable for the miniaturization design of microwave circuits.

[0021] In an optional embodiment of the present invention, each of the signal input port Port1 and the signal output port Port2 has a pad on both sides and is grounded through a grounding via to form a ground-signal-ground (GSG) structure, which facilitates probe testing.

[0022] Figure 3Performance curves for a preferred embodiment are presented, showing that the filter achieves reflection-free characteristics within 120% of its relative bandwidth. The results demonstrate that the reflection-free bandpass filter chip based on the Lange bridge proposed in this invention possesses a wide reflection-free bandwidth.

Claims

1. A reflection-free bandpass filter chip based on a Lange bridge, characterized in that, include: A dielectric substrate and a reflection-free bandpass filter disposed on the dielectric substrate. The reflection-free bandpass filter includes a first Lange bridge (Q1), a second Lange bridge (Q2), a first bandpass filter (F1), a second bandpass filter (F2), a first absorption resistor (R1), and a second absorption resistor (R2). One end of the first bandpass filter (F1) and the second bandpass filter (F2) are respectively connected to a power splitting coupling port of the first Lange bridge (Q1), and the other end of the first bandpass filter (F1) and the second bandpass filter (F2) are respectively connected to a power splitting coupling port of the second Lange bridge (Q2). The remaining two ports of the first Lange bridge (Q1) are used as signal input port Port1 and grounded through the first absorption resistor (R1). The remaining two ports of the second Lange bridge (Q2) are used as signal output port Port2 and grounded through the second absorption resistor (R2).

2. The reflection-free bandpass filter chip based on Lange bridge according to claim 1, characterized in that, The first Lange bridge (Q1) and the second Lange bridge (Q2) have the same structure.

3. The reflection-free bandpass filter chip based on Lange bridge according to claim 2, characterized in that, The first bandpass filter (F1) and the second bandpass filter (F2) have the same structure, adopting a fifth-order structure, consisting of two series resonators and three parallel resonators. The two series resonators are connected in series, and one end of the parallel resonator is connected in the series resonator circuit, while the other end is grounded.

4. The reflection-free bandpass filter chip based on Lange bridge according to claim 2, characterized in that, The first bandpass filter (F1) includes a first inductor L1, a first capacitor C1, a second inductor L2, a second capacitor C2, a third inductor L3, a third capacitor C3, a fourth inductor L4, a fourth capacitor C4, a fifth inductor L5, and a fifth capacitor C5. The second inductor L2, the second capacitor C2, the fourth inductor L4, and the fourth capacitor C4 are connected in series. The first inductor L1 and the first capacitor C1 are connected in parallel, with one end grounded and the other end connected to the end of the second inductor L2 away from the second capacitor C2. The third inductor L3 and the third capacitor C3 are connected in parallel, with one end grounded and the other end connected to the junction of the second capacitor C2 and the fourth inductor L4. The fifth inductor L5 and the fifth capacitor C5 are connected in parallel and to the end of the fourth capacitor C4 away from the fourth inductor L4.

5. The reflection-free bandpass filter chip based on Lange bridge according to claim 1, characterized in that, The dielectric substrate is made of GaAs material.

6. The reflection-free bandpass filter chip based on Lange bridge according to claim 1, characterized in that, Each of the signal input port Port1 and signal output port Port2 has a pad on one side and is grounded through a grounding via.

7. The reflection-free bandpass filter chip based on Lange bridge according to claim 1, characterized in that, The first Lange bridge (Q1) and the second Lange bridge (Q2) are constructed using a method of multiple bends and loops.

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