CN-224218371-U - Circuit structure of 108MHz-678 MHz high-suppression large-bandwidth electrically tunable filter

CN224218371UCN 224218371 UCN224218371 UCN 224218371UCN-224218371-U

Abstract

The utility model discloses a circuit structure of a 108MHz-678 MHz high-suppression large-bandwidth electrically-tunable filter, which belongs to the technical field of electrically-tunable filters and comprises a circuit structure of a 108MHz-225 MHz tuning filter, a circuit structure of a 225 MHz-400 MHz tuning filter, a circuit structure of a 108MHz-225 MHz tuning filter and a circuit structure of a 108MHz-678 MHz direct-connection channel, wherein one end of each circuit structure of the 108MHz-225 MHz tuning filter, the 225 MHz-400 MHz tuning filter, the 108MHz-225 MHz tuning filter and the circuit structure of the 108MHz-678 MHz direct-connection channel is connected with a radio frequency switch U1, the other end of each circuit structure of the 108MHz-678 MHz direct-connection channel is respectively connected with three low-pass filters and a radio frequency switch U2, the other ends of the three low-pass filters are connected with the radio frequency switch U2, and a main magnetic ring inductor of the electrically-tunable filter uses a hollow coil wound by an enameled wire. The size of the electrically tunable filter is reduced by reducing the number of the inductors, and the pins are prevented from being damaged by the test fixture, so that the test efficiency and the accuracy are improved.

Inventors

JIA KUN
DENG SHICHUN
XIAO SONG
WANG HUAN
WU SHOUCHAO

Assignees

贵阳信络电子有限公司

Dates

Publication Date: 20260508
Application Date: 20250530

Claims (3)

1. A circuit structure of a 108 MHz-678 MHz high-suppression large-bandwidth electrically-tunable filter is characterized by comprising a circuit structure of a 108 MHz-225 MHz tuning filter, a circuit structure of a 225 MHz-400 MHz tuning filter, a circuit structure of a 108 MHz-225 MHz tuning filter and a circuit structure of a 108 MHz-678 MHz through path, one end of the circuit structure of the 108 MHz-225 MHz tuning filter, the circuit structure of the 225 MHz-400 MHz tuning filter, the circuit structure of the 108 MHz-225 MHz tuning filter and the circuit structure of the 108MHz-678 MHz through path is connected with a radio frequency switch U1, the circuit structure of the 108 MHz-225 MHz tuning filter, the circuit structure of the 225 MHz-400 MHz tuning filter and the circuit structure of the 108MHz-225 MHz tuning filter are respectively connected in series with an LTCC low-pass filter LFCN3216-190A01, an LTCC low-pass filter LFCN3216-420A01 and an LTCC low-pass filter LFCN3216-575A01, an LTCC low-pass filter LFCN3216-190A01, an LTCC low-pass filter LFCN3216-420A01 and the circuit structure of the LTCC low-pass filter LFCN3216-575A01 and the circuit structure of the 108 MHz-678 MHz through path, and the other end of the circuit structure of the electrically tuning filter is connected with a radio frequency switch U2, and a main inductor of the electrically tuning filter uses a hollow coil wound by a enameled wire.
2. The circuit structure of a 108 MHz-678 MHz high-rejection large bandwidth electrically tunable filter as set forth in claim 1, wherein the circuit structure of the 108 MHz-225 MHz tuned filter, the circuit structure of the 225 MHz-400 MHz tuned filter, the circuit structure of the 108 MHz-225 MHz tuned filter and the circuit structure of the 108 MHz-678 MHz through path each comprise an inductor L1, an inductor L2, an inductor L3, an inductor L4, an inductor L5, an inductor L6, a capacitor C1 and a capacitor C2, the inductor L5, the inductor L1, the inductor L2 and the inductor L6 are sequentially connected in series, the other end of the inductor L5 is connected to a radio frequency switch U1, the inductor L6 is directly or after being connected with a LTCC low-pass filter in series, one end between the inductor L5 and the inductor L1 is connected to one end of the inductor L3, the other end of the inductor L3 is connected to one end of the capacitor C1, one end between the inductor L2 and the inductor L6 is connected to one end of the inductor L4, the other end of the inductor L4 is connected to one end of the capacitor C2, and the other end of the capacitor C1 and one end of the inductor L2 is connected to the inductor L2.
3. The circuit structure of the 108 MHz-678 MHz high-suppression large-bandwidth electrically tunable filter according to claim 2, wherein the inductance L4, the inductance L1, the inductance L2 and the inductance L3 all use enameled wires of an air-core coil, and the enameled wires are welded on different positions to a bonding pad to obtain four inductors.

Description

Circuit structure of 108MHz-678 MHz high-suppression large-bandwidth electrically tunable filter Technical Field The utility model relates to a circuit structure of a 108 MHz-678 MHz high-suppression large-bandwidth electrically tunable filter, and belongs to the technical field of electrically tunable filters. Background The electrically tunable filter shown in fig. 8 includes a housing and a coil enclosed in the housing and pins provided at the bottom of the housing, the pins being defined as shown in table 1 below. Table 1 electrically tunable filter pin definition Pin numberingCorresponding definition1GND2VCC3VT4GND5GND6RF7GND8GND9GND10GND11RF12GND13GND14GND15D116D0 Excellent filters require a smaller insertion loss and a better rejection of plus or minus 10% at any center frequency, and a greater rejection of the far end at twice the center frequency. Since insertion loss is inversely proportional to the positive and negative 10% rejection of any center frequency, one indicator is good and the other indicator is bad. Meanwhile, the positive and negative 10% inhibition of any center frequency is inversely proportional to the far-end inhibition at the position of twice the center frequency, one index is good, and the other index is poor. Therefore, when the insertion loss of the electrically tunable filter cannot be smaller than or equal to 4dB under the same size, and when the plus or minus 10% inhibition of any center frequency of 225 MHz-678 MHz is larger than or equal to 13dBc, the far-end inhibition at the position of twice the center frequency is larger than 22 dB-26 dB, and the electrically tunable filter cannot be used by users. Disclosure of utility model The utility model aims to solve the technical problems by providing a circuit structure of a 108 MHz-678 MHz high-suppression large-bandwidth electrically tunable filter. The technical scheme includes that the circuit structure of the 108MHz-678 MHz high-suppression large-bandwidth electrically-tunable filter comprises a circuit structure of the 108MHz-225 MHz tuned filter, a circuit structure of the 225 MHz-400 MHz tuned filter, a circuit structure of the 108MHz-225 MHz tuned filter and a circuit structure of a 108MHz-678 MHz direct-through channel, a circuit structure of the 225 MHz-400 MHz tuned filter, a circuit structure of the 108MHz-225 MHz tuned filter and a circuit structure of the 108MHz-678 MHz direct-through channel, one end of the circuit structure of the 108MHz-225 MHz tuned filter is connected with a radio frequency switch U1, the circuit structure of the 225 MHz-400 MHz tuned filter, the circuit structure of the 225 MHz-225 MHz tuned filter is connected with an LTCC low-pass filter LFCN-190A 01, an LTCC low-pass filter LFCN3216-420A01 and an LTCC low-pass filter 32132A 01, an LTCC low-32124-575A 01, an LTCC low-pass filter LFCN-3216-190A 01, an LTCC low-pass filter 420A 25-band is connected with an LTCC low-pass filter 35A 01 in series, and the other end of the circuit structure of the power-band is connected with a magnetic loop of the main coil of the power transmission device, and the main coil of the power filter is connected with the main coil of the power filter. Further, the circuit structure of the 108MHz-225 MHz tuning filter, the circuit structure of the 225 MHz-400 MHz tuning filter, the circuit structure of the 108MHz-225 MHz tuning filter and the circuit structure of the 108MHz-678 MHz through-path all comprise an inductor L1, an inductor L2, an inductor L3, an inductor L4, an inductor L5, an inductor L6, a capacitor C1 and a capacitor C2, the inductor L5, the inductor L1, the inductor L2 and the inductor L6 are sequentially connected in series, the other end of the inductor L5 is connected to a radio frequency switch U1, the inductor L6 is directly connected with or connected with an LTCC low-pass filter in series and then is connected with the radio frequency switch U2, one end between the inductor L5 and the inductor L1 in series is connected to one end of the inductor L3, the other end of the inductor L3 is connected to one end of the capacitor C1, one end between the inductor L2 and the inductor L6 in series is connected to one end of the inductor L4, the other end of the inductor L4 is connected to one end of the capacitor C2, the other end of the capacitor C1 and one end of the inductor L2 in series is grounded. The filter is divided into a capacitor and an inductor, when the inductor is kept unchanged, the capacitors C1 and C2 are varactors, and according to the characteristics of the varactors, tunable reverse bias voltage VT is provided for the varactors, so that the change of capacitance values is realized, and the purposes of changing resonance frequency and realizing frequency conversion are achieved. Further, the inductance L4, the inductance L1, the inductance L2 and the inductance L3 all use enameled wires of an air core coil, and are respectively welded at different positions on the bonding pad to o