CN105140612A - Dual-frequency-band electrically-tunable filtering type power divider - Google Patents

Abstract

The invention discloses a dual-frequency-band electrically-tunable filtering type power divider and belongs to the technical field of microwave passive devices. According to the invention, a tunable filter is integrally arranged in the power divider, the complexity and the size of the power divider are reduced, and the power divider is provided with a dual-frequency independent adjustment function. According to the innovative scheme, adjusting elements which are first varactors (4) and a varactor (8) select access points independent in frequency modulation to carry out individual adjustment on two frequency bands. The dual-frequency-band electrically-tunable filtering type power divider can be applied to a microwave communication system and is applicable to a system small in size, low in cost and high in integration.

Description

A dual-band electronically adjustable filter type power divider

technical field

The invention belongs to the technical field of microwave passive devices, and in particular relates to a dual-band electric control filter type power divider in microwave passive devices.

Background technique

With the rapid development of modern communication systems, the functions of microwave circuits are becoming more and more complex, and the electrical performance requirements are getting higher and higher. At the same time, they are also developing in the direction of miniaturization, light weight, and low cost. This development trend is formed in order to meet the commercial requirements of microwave circuits. The multi-functionality of the device and the adjustable performance of the device are effective ways to reduce the size of the circuit. For example, the power divider and filter coexisting in the same transceiver front end can be integrated together to form a power divider with filtering characteristics. With adjustable technology, the size, complexity and cost of the circuit can be greatly reduced.

Ordinary power splitters with filtering characteristics add filtering characteristics to the quarter-wavelength power splitting arm. Although the size is reduced, the number of filters is doubled. The existing power splitters with adjustable filtering characteristics only realize single-band adjustable characteristics. For microwave systems that require multi-band adjustable, multiple power splitters with adjustable filtering characteristics working in corresponding frequency bands are required. device, the cost increases the complexity, volume and cost of the power dividing circuit.

Contents of the invention

The purpose of the present invention is to propose a dual-band electronically adjustable filter type power splitter, which integrates a filter inside to realize the additional filtering characteristics of the power splitter, and adopts a dual-frequency structure to load two sets of varactors , to realize the dual working frequency band adjustable characteristics of the power divider.

Technical scheme of the present invention is:

A dual-band electronically adjustable filter type power splitter, the input end of the power splitter is composed of a straight 50 ohm microstrip line, after the microstrip line, it is divided into two symmetrical branches, and each branch is coupled in parallel by the input Line, bent microstrip line, two first varactors, two pairs of metallized through holes and output parallel coupling lines; one end of the two first varactors is connected between the two bent microstrip lines, and two pairs of metal The other end of the two first varactors is connected to the floor through the through-hole; finally, it is output by two bent 50-ohm microstrip lines, and the 100-ohm resistor is connected to the starting end between the two bent 50-ohm microstrip lines ; In the middle of the input parallel coupling line and the output parallel coupling line is the second varactor, the first chip capacitor and the second chip capacitor are closely symmetrically distributed above and below the second varactor, the first chip capacitor and the second chip capacitor The two chip capacitors are respectively connected to the center points of the input parallel coupling line and the output parallel coupling line; on the upper side of the second varactor, the pull-up resistor and the DC bias pad are connected in turn, and under the second varactor The side end is also connected to the bent connection line, the chip resistor and the metalized through hole in sequence; the pull-up resistor and the DC bias pad are connected in the middle of the output parallel double line in sequence.

Further, the bent microstrip line, the input parallel coupling line, and the output parallel coupling line have the same line width, and the interior of the three forms a rectangle.

Further, the straight line formed by the second varactor, the first chip capacitor and the second chip capacitor is collinear with the straight 50 ohm microstrip line, and is perpendicular to the chip resistor and the metallized through hole, and is connected to the pull-up resistor, The DC bias pad, the pull-up resistor, and the DC bias pad form a π shape.

Advantages and beneficial effects of the present invention:

(1) The present invention has the advantages of miniaturization and low cost. On the one hand, the use of dual-frequency technology reduces the size of the circuit by half compared to the dual-frequency achieved by ordinary cascaded single-frequency filters; on the other hand, the low-frequency adjustable components of the power divider share a varactor , and the bias circuit of the varactor; thereby greatly reducing the size and cost of the overall circuit, and reducing the differential loss of the circuit.

(2) The power splitter of the present invention has independent dual-band adjustable filtering characteristics, the adjustment between the two frequency bands is independent of each other, and the adjustment of a single frequency band does not affect the other frequency band.

Description of drawings

Fig. 1 is a structural representation of the present invention

Fig. 2 is the simulation result of the low frequency independently adjustable of a kind of specific structure of the present invention

Fig. 3 is a kind of high-frequency independent adjustable simulation result of specific structure of the present invention

Detailed ways

In order to make the object of the present invention, the technical problem to be solved and the technical solution clearer, the present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

Fig. 1 is a structural schematic diagram of a specific implementation example of the present invention. The power divider is a Wilkinson type power divider. The input end is composed of a straight 50 ohm microstrip line 1 with a line width of 1.1mm. After the microstrip line, it is divided into two symmetrical branches, and each branch is parallel to the input. Coupling line 2, bent microstrip line 3, two first varactors 4, two pairs of metallized through-holes 5 and output parallel coupling lines 6 constitute two left and right 90-degree phase-shifting resonators with filtering characteristics, It is equivalent to a power branch with an electrical length of 1/4 wavelength and a characteristic impedance of 70.7 ohms. The lengths of the input parallel coupling line 2 and the output parallel coupling line 6 are both 10 mm. One end of the two first varactors 4 is connected between the two bent microstrip lines 3 , and two pairs of metallized through holes 5 connect the other ends of the two first varactors 4 to the floor. Finally, it is output by two bent 50-ohm microstrip lines 7 , and a 100-ohm resistor 17 is connected to the starting end between the two bent 50-ohm microstrip lines 7 . In the middle of the input parallel coupling line 2 and the output parallel coupling line 6 is the second varactor 8, the first chip capacitor 11 and the second chip capacitor 14 are closely symmetrically distributed above and below the second varactor 8, the first The chip capacitor 11 and the second chip capacitor 14 are connected to the center of the input parallel coupling line 2 and the output parallel coupling line 6 respectively. At the upper end of the second varactor 8, a pull-up resistor 12 and a DC bias pad 13 are connected in sequence, and at the lower end of the varactor 8, a bent connecting wire 18 and a chip resistor 9 are also connected in sequence. and metallized vias 10 . The pull-up resistor 16 and the DC bias pad 15 are sequentially connected in the middle of the output parallel double lines. The first varactor 4 and the second varactor 8 only affect the even-mode resonant frequency and the odd-mode resonant frequency respectively, therefore, the filter type power splitter can work in independently adjustable dual frequency bands. The diameter of the metallized through hole is 0.5mm.

Further, the bent microstrip line 3 , the input parallel coupling line 2 and the output parallel coupling line 6 have the same line width of 0.5 mm, and the three are enclosed inside a rectangle of 4.8 mm×36 mm.

Further, the straight line formed by the second varactor 8, the first chip capacitor 11 and the second chip capacitor 14 is collinear with the straight line 50 ohm microstrip line 1, and is perpendicular to the chip resistor 9 and the metallized through hole 10 , form a π shape with the pull-up resistor 12, the DC bias pad 13, the pull-up resistor 16, and the DC bias pad 16.

The dielectric substrate used in the filter power splitter is TaconicRF-35, the thickness of the dielectric substrate is 0.508mm, the thickness of the upper and lower layers of metal copper foil is 18um, and the final substrate size is 26mm×43mm. Varactors 4 and 8 are both InfineonBB857, and the adjustable range of capacitance is 0.5pF-6.5pF; SMD capacitors 11 and 14, the capacitance is 0.5pF, the package is 0402, and the package of 100 ohm resistor 17 is 0603 , Two pull-up resistors 12 and 16, the resistance value is 10kohm, the package is 0603, the chip inductor is 9, the inductance value is 20nH, and the package is 0603.

Fig. 2 is the low-frequency individually adjustable simulation result of this specific implementation example. It can be seen that: when the capacitance value of the fixed varactor 8 is 0.5pF, and the varactor 4 changes from 0.5pF to 1.5pF, the filter type power divider The center frequency of the low frequency band of the device changes from 1400MHz to 1700MHz, the adjustable range is 300MHz, and the center frequency of the high frequency band remains at 3400MHz.

Fig. 3 is the high-frequency independent adjustable simulation result of this specific implementation example, it can be seen that: when the capacitance value of the fixed varactor 4 is 0.5pF, and the varactor 8 changes from 0.5pF to 1.0pF, the filter type power The center frequency of the low frequency band of the splitter remains at 1700MHz, and the center frequency of the high frequency band changes from 3000MHz to 3400MHz, and the adjustable range is 400MHz.

At the same time, at all working center frequencies, the isolation is better than 15dB, the input reflection loss is better than 10dB, the low-frequency insertion loss is less than 4.3dB, and the high-frequency insertion loss is less than 2.0dB.

Those skilled in the art will appreciate that the embodiments described here are to help readers understand the principles of the present invention, and it should be understood that the protection scope of the present invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific modifications and combinations based on the technical revelations disclosed in the present invention without departing from the present invention, and these modifications and combinations are still within the protection scope of the present invention.

Claims (3)

1. a two-band electrically regulated filtering type power splitter, it is characterized in that: the input of this power splitter is made up of straight line 50 ohm microstrip (1), after microstrip line, be divided into symmetrical two branch roads, every bar props up route input parallel coupled line (2), bending microstrip line (3), two the first varactors (4), two pairs of plated-through holes (5) and exports parallel coupled line (6) composition; Two the first varactor (4) one end are connected in the middle of two bending microstrip lines (3), and the other end of two the first varactors (4) is connected to floor by two pairs of plated-through holes (5); Finally exported by two bendings 50 ohm microstrip (7), 100 Ohmic resistances (17) are connected on the initiating terminal between two bendings 50 ohm microstrip (7); Input parallel coupled line (2) and output parallel coupled line (6) middle are the second varactor (8), first patch capacitor (11) and the second patch capacitor (14) are close to and are symmetrically distributed in the second varactor (8) upper and lower, the first patch capacitor (11) and the second patch capacitor (14) respectively with input parallel coupled line (2) with export parallel coupled line (6) central point and be connected; In the second varactor (8) upside, also be connected to pull-up resistor (12) and direct current biasing pad (13) successively, in the second varactor (8) lower side, be also connected to bending connecting line (18), Chip-R (9) and plated-through hole (10) successively; Pull-up resistor (16) and direct current biasing pad (15) are connected in turn and export parallel wire middle.

2. a kind of two-band electrically regulated filtering type power splitter according to claim 1, it is characterized in that: bending microstrip line (3), input parallel coupled line (2) are identical with exporting parallel coupled line (6) live width, and three inside surrounds rectangle.

3. a kind of two-band electrically regulated filtering type power splitter according to claim 1, it is characterized in that: the straight line that the second varactor (8), the first patch capacitor (11) and the second patch capacitor (14) are formed and straight line 50 ohm microstrip (1) conllinear, and perpendicular to Chip-R (9) and plated-through hole (10), form π type with pull-up resistor (12), direct current biasing pad (13) and pull-up resistor (16), direct current biasing pad (15).