CN104716408A - Continuous variable substrate integrated waveguide analog phase shifter - Google Patents

Abstract

The invention relates to a microwave circuit technology, in particular to a continuous variable substrate integrated waveguide analog phase shifter. The continuous variable substrate integrated waveguide analog phase shifter comprises a 50-omega characteristic impedance microstrip line, a variable capacitance diode, a transition structure, a substrate integrated waveguide (SIW) and a periphery resistor, capacitor and inductor. The input end of the microstrip line has 50-omega characteristic impedance, and a signal is fed to the SIW through the transition structure. In the SIW, a groove is formed in the transmission direction of an electromagnetic field, the SIW is divided into two parts through the groove line, the width of the side, comprising the transition structure, of the SIW is W, and the width of the other side is C. The transition structure is in a concave rectangle shape. The variable capacitance diode and a fixed capacitance value capacitor are installed on the two sides of the groove line in pairs and are perpendicular to the SIW. The phase of the phase shifter is continuously variable along with tuning voltage, the bandwidth is large, the transmission loss is small, the reflection coefficient is small, the phase shifting range is large, and the continuous variable substrate integrated waveguide analog phase shifter is conveniently integrated in a circuit.

Description

A Continuously Variable Substrate Integrated Waveguide Analog Phase Shifter

technical field

The patent of the present invention relates to microwave circuit technology, especially a continuously variable substrate integrated waveguide (Substrate Integrated Waveguide, SIW) analog phase shifter.

technical background

Phase shifter is an important microwave device. Its main function is to shift the phase of signals in a certain frequency range. It is often used in phased array antennas, test equipment, and orthogonal decomposition of signals. A phase shifter is a two-port microwave network that generates a variable phase difference between the input and output signals of the network through a control signal. According to different working principles, it can be divided into digital phase shifters and analog phase shifters. .

Substrate-integrated waveguide (SIW) is a novel microwave transmission line, which uses metal vias to obtain field propagation modes similar to waveguides on dielectric substrates. It has high Q value, small transmission loss, easy processing and realization, small volume, and low cost Low-level advantages have become a research hotspot in the field of microwave and millimeter waves.

In related research reports, the substrate integrated waveguide phase shifter mainly adopts three methods to realize. In 2012, K.Sellal realized a four-bit digital substrate integrated waveguide stepping phase shifter based on the embedded PIN switching diode, see the literature K.Sellal, L.Talbi, and M.Nedil, "Design and implementation of a controllable phase shifter using substrate integrated waveguide,” IET Microw. Antennas Propag., vol.6, no.9, pp.1090–1094, Apr.2012.

Researcher Tao Yang designed five substrate-integrated waveguide phase shifters with different degrees of phase shifting, using microwave switches to select the required channels, see the literature T. Yang, M. Ettorre, and R. Sauleau, "Novel phase shifter design based on substrate integrated waveguide technology,” IEEE Microw. Wireless Compon. Lett., vol.22, no.10, pp.518–520, Oct.2012.

Both of the above two phase shifters can be regarded as digital phase shifters. In addition, the researchers also studied the continuously adjustable analog phase shifter based on the terminal reflection type. By controlling the external voltage to change the capacitance of the varactor diode, the complex reflection coefficient of the reflective end face is changed to realize the phase change of the output signal. See Literature Yan Ding, and Ke Wu, "Varactor-tuned substrate integrated waveguide phaseshifter," Microwave Symposium Digest, IEEE Mtt-s International.IEEE, 2011:1-4. However, the circuit structure of this reflective phase shifter is more complicated, and A 3dB coupler needs to be designed.

Contents of the invention

In view of the above-mentioned problems or deficiencies, the present invention provides a continuously variable substrate-integrated waveguide analog phase shifter, including a 50Ω characteristic impedance microstrip line, a varactor diode, a transition structure, a substrate-integrated waveguide and peripheral resistors, capacitors, inductors ; The structural feature of the phase shifter is: the input end is a microstrip line with 50Ω characteristic impedance, and the signal is fed to the substrate integrated waveguide SIW through the transition structure. In the SIW structure working in the full-mode mode, a slot is opened along the electromagnetic field propagation direction, the slot length is the same as the SIW length, and the width s≤1.5mm; this slot line divides the substrate integrated waveguide into two parts, including a transition structure. The width of SIW on one side is W, the width on the other side is C, the transition structure is a concave rectangle, the length along the direction of electromagnetic field propagation is 1/3W≤l _x ≤2/3W, and the length of the other side is 1/ _5W≤ly ≤2 /3W.

Pairs of varactor diodes and fixed-capacity capacitors are installed on both sides of the slot line perpendicular to the SIW, and the two lines are perpendicular to the slot line. The center distance between each pair of varactor diodes V _CD and fixed-capacity capacitor C _m is s <l _t ≤2mm, the distance between two adjacent pairs of varactor diodes and fixed capacitance capacitors is 5mm≤l _s ≤10mm.

Peripheral resistance, capacitance and inductance: the anode of the varactor diode is grounded on one side of the slot line with solder, one end of the fixed capacitance C _m is grounded on the other side of the slot line with solder, and the negative pole of the varactor diode and the other end of C _m are connected by solder They are connected together, and then connected in series with the choke inductance L _n and the current limiting resistor R _n through wires, and connected in parallel with the decoupling capacitor C _n to the ground. The capacitance of C _m is 100 times greater than the maximum capacitance of the varactor diode.

The number of pairs of varactor diodes and fixed capacitance capacitors is less than 30 pairs.

The working principle of the present invention is: use the external control voltage to change the capacitance of the diode, so that the electric field distribution of the substrate integrated waveguide on both sides of the slot line changes, thereby causing the phase lag and/or advance of the electromagnetic field propagating in the substrate integrated waveguide , and finally realize the phase shift function.

The beneficial results of the invention are: simple structure, convenient processing and low cost, and can be realized by using the ready-made substrate integrated waveguide structure. The phase change of the phase shifter is continuously variable with the tuning voltage, the bandwidth is wide, the transmission loss is small, the reflection coefficient is small, the phase shift range is large, and it is convenient to be integrated in a circuit.

Description of drawings

Fig. 1 is a top view of the substrate integrated waveguide part of the embodiment of the present invention;

Fig. 2 is a schematic diagram of a side installation of a single varactor diode according to an embodiment of the present invention;

Fig. 3 is the relation of varactor diode voltage and capacitance value of the embodiment of the present invention;

Fig. 4 is the relationship between the varactor capacitance and the phase of the embodiment of the present invention;

Fig. 5 is the transmission parameter of the embodiment of the present invention;

Fig. 6 is the reflection coefficient of the embodiment of the present invention;

Reference numerals: metallized through hole-1, transition structure-2, varactor diode and fixed capacitance diode-3, SIW body-4, slot line-5.

Detailed ways

The continuously variable substrate-integrated waveguide analog phase shifter is implemented on a RT/Duroid 4350 dielectric substrate with a thickness of 0.508mm. The relative dielectric constant of the substrate is 3.48 and the loss tangent is 0.0037. As shown in Figure 1, the input end is a 50Ω characteristic impedance microstrip line, and the signal is fed to the substrate integrated waveguide through the transition structure. A slot is opened in the SIW structure along the direction of electromagnetic field propagation, and the slot length is the same as the SIW length. The slot line divides the substrate integrated waveguide into two parts, and two rows of varactor diodes V _CD and fixed capacitance capacitors C _m are vertically installed on the left and right sides of the slot line at equal intervals l _s . In order to reduce the influence of distributed parameters, Devices in tiny packages (such as 0402 packages) will be selected.

Figure 2 shows the installation method of the varactor diode, the anode of the varactor diode is grounded on one side of the slot line with solder, and one end of the fixed capacitance C _m is grounded on the other side of the slot line with solder (C _m is taken as 100pF) . The function of C _m is to isolate the direct current, and at the same time reduce the influence on the parallel equivalent capacitance value of the whole circuit. The negative pole of the varactor diode and the other end of C _m are connected together by solder, and then connected in series with the choke inductance L _n and the current limiting resistor R _n respectively through wires, and connected in parallel with the decoupling capacitor C _n to the ground. We choose a single varactor with a capacitance variation range of 0.23pF-2.1pF and an equivalent series resistance of less than 1Ω.

Continuous phase shifter among the present invention is realized in professional electromagnetic field simulation software, adopts the high frequency structure simulation software (High Frequency Structure Simulator, HFSS) of Ansoft Company to carry out modeling simulation, and parameter definition is as follows: w _ms is microstrip line width , l _ms is the length of the microstrip line, w is the width of the SIW including one side of the transition structure, c is the width of the integrated waveguide on the other side of the substrate, s _vp is the spacing of the metallized vias, d _vp is the diameter of the metallized vias, l is the length of the integrated waveguide on the substrate, s is the slot width, l _s is the distance between two adjacent varactor diodes V _CD and fixed capacitance capacitor C _m , l _t is each pair of varactor diode V _CD and fixed capacitance capacitor C _m is the center distance, l _x is the width of the transition structure, and _ly is the length of the transition structure. After optimization and simulation, the optimal parameter size is obtained, as follows: w _ms = 1.12mm, l _ms = 6mm, c = 3mm, w = 15mm, s _vp = 0.75mm, d _vp = 0.5mm, l = 130mm, s =0.5 mm, l _s =8 mm, l _t =1.4 mm, l _x =6.5 mm, l _y =5 mm.

Figure 3 shows the relationship between the reverse voltage and capacitance of the varactor diode. It can be seen that the voltage and capacitance are inversely proportional to nonlinearity. FIG. 4 shows a phase diagram of a phase shifter simulation, FIG. 5 shows a transmission characteristic diagram of a phase shifter simulation, and FIG. 6 shows a reflection coefficient diagram of a phase shifter simulation.

It can be seen from the simulation results that when the corresponding varactor diode capacitance range is 0.5pF-1pF, the phase shifter can perform phase adjustment in the frequency range of 2.68-3.5GHz, the relative bandwidth is 26.5%, and the voltage adjustment range It is 3-6.5V, the phase shift range is greater than 145°, the transmission parameter is better than -3dB, and the reflection coefficient is better than -10dB.

Claims (3)

1. the substrate integration wave-guide analog phase shifter of a continuously variable type, comprise 50 Ω characteristic impedance microstrip lines, variable capacitance diode, transition structure, substrate integration wave-guide SIW and peripheral resistance capacitance inductance, it is characterized in that: input is the microstrip line of 50 Ω characteristic impedances, and signal is fed to substrate integration wave-guide through transition structure again; In the SIW structure working in full mould pattern, open a groove along the electromagnetic field direction of propagation, flute length is identical with SIW length, width s≤1.5mm; Substrate integration wave-guide is divided into two parts by this line of rabbet joint, and the SIW width comprising transition structure side is W, and opposite side width is C, and transition structure is the rectangle of depression, its length 1/3W along the electromagnetic field direction of propagation≤l _x≤ 2/3W, another side length 1/5W≤l _y≤ 2/3W;

Variable capacitance diode and fixing capacitance electric capacity are arranged on line of rabbet joint both sides respectively perpendicular to SIW in pairs, and both lines are vertical with the line of rabbet joint, often couple of variable capacitance diode V _cDwith fixing capacitance electric capacity C _mcentre distance s < l _t≤ 2mm, the distance 5mm≤l between adjacent two pairs of variable capacitance diodes and fixing capacitance electric capacity _s≤ 10mm;

Peripheral resistance capacitance inductance: the positive pole scolding tin of variable capacitance diode, line of rabbet joint side ground connection, fixes capacitance electric capacity C _mone end scolding tin line of rabbet joint opposite side ground connection, the negative pole of variable capacitance diode and C _mthe other end connected together by scolding tin, then through wire respectively with choke induction L _nwith current-limiting resistance R _nseries connection, simultaneously with decoupling capacitor C _nearth, wherein C _mcapacitance is greater than the maximum capacitance of variable capacitance diode 100 times.

2. the substrate integration wave-guide analog phase shifter of continuously variable type as claimed in claim 1, is characterized in that: it is 30 right that the logarithm of described variable capacitance diode and fixing capacitance electric capacity is less than.

3. the substrate integration wave-guide analog phase shifter of continuously variable type as described in as arbitrary in claim 1 or 2, is characterized in that: SIW selects thickness to be the RT/Duroid 4350 of 0.508mm, and relative dielectric constant is 3.48, and loss angle tangent is 0.0037, C _mget 100pF; Wherein w _msfor micro belt line width, l _msfor microstrip line length, s _vpfor plated-through hole spacing, d _vpfor plated-through hole diameter, l is substrate integration wave-guide length;

The concrete size of each parameter is as follows: w _ms=1.12mm, l _ms=6mm, c=3mm, w=15mm, s _vp=0.75mm, d _vp=0.5mm, l=130mm, s=0.5mm, l _s=8mm, l _t=1.4mm, l _x=6.5mm, l _y=5mm.