Plasma waveguide phase shifter

Abstract

The present invention discloses a plasma waveguide phase shifter, which belongs to the field of radio frequency communication technology. The phase shifter uses waveguide as the basic carrier and combines the relevant technologies of solid semiconductor plasma to realize the phase change of electromagnetic waves inside the waveguide. The phase shifter mainly includes two parts: waveguide and solid semiconductor plasma. The waveguide can be used in various forms. The solid semiconductor plasma has the characteristics of small size and independent control. It can be designed according to the design ideas of traditional digital phase shifters, or it can be designed as a continuously adjustable phase shifter. Compared with traditional phase shifters, the phase shifter of the present invention has the following main advantages: low insertion loss; flexible design, solid semiconductor plasma can be integrated on the inner wall of waveguide of any structure; great advantages for high-frequency use; convenient and simple control, solid semiconductor plasma has only two states, and the state change can be simply realized by external voltage control.

Description

Technical Field

[0001] The invention belongs to the technical field of radio frequency communication, and in particular relates to a novel solid semiconductor plasma waveguide phase shifter which is different from the traditional concept. Background Art

[0002] Phase shifters play a wide and important role in radar, communication and other fields. In different usage scenarios, there are different requirements for the structure and RF performance of phase shifters. Therefore, phase shifters include a variety of different types: fixed phase shifters, adjustable phase shifters, waveguide phase shifters, ferrite phase shifters, microstrip phase shifters, etc. With the continuous development of communication technology, the requirements for miniaturization of electronic devices are constantly increasing, and the application of millimeter wave frequency bands is becoming more and more extensive. However, the increase in frequency makes it more difficult to solve various problems such as RF device loss and heat dissipation. For phase shifters in the RF field, the requirements for miniaturization, phase accuracy, control complexity, heat dissipation, etc. are becoming higher and higher. Relatively mature microstrip phase shifters and fixed phase shifters are subject to many restrictions when used at relatively high frequencies.

[0003] To address the above issues, no effective solutions have been proposed so far. Summary of the invention

[0004] The objectives of the present invention are achieved through the following technical solutions.

[0005] In view of this, the present invention provides a new type of solid semiconductor plasma waveguide phase shifter to adapt to higher frequency band applications. Compared with traditional phase shifters, the phase shifter of the present invention has the characteristics of flexible design. It can be designed as a phase shifter with a fixed phase shift amount or used as a digital phase shifter, and the phase shift step can be flexibly designed according to actual needs.

[0006] The present invention is directed to a metal rectangular waveguide for transmitting radio waves, which can be a hollow waveguide or a dielectric waveguide. In order to maximize the transmission efficiency, the electromagnetic wave propagates in the fundamental mode, i.e., the TE10 mode. The present invention places the solid semiconductor plasma on the inner side of the narrow side of the rectangular waveguide, and the phase shift is achieved by utilizing the different reactions of the dielectric properties of the solid semiconductor plasma to the voltage. When the solid semiconductor plasma unit is not driven by a DC voltage, it behaves as a semiconductor medium, and when the solid semiconductor plasma unit is driven by a DC voltage, it behaves as a good conductor like a metal. Through the power-on treatment, the conductivity of the solid semiconductor plasma is greatly improved, and it can be approximately regarded as a material close to a metal, and its position is on the inner wall of the narrow side of the waveguide, which is equivalent to compressing the long side of the waveguide, so that the frequency of the electromagnetic wave propagating in the new fundamental mode will increase, and the frequency of the electromagnetic wave corresponding to the fundamental mode propagating in the original waveguide will change. The change of the fundamental mode leads to the difference in phase before and after power-on, thereby achieving the purpose of phase shift. The following will be specifically explained from the structural point of view.

[0007] The present invention is based on the BJ320 waveguide and designs two forms of phase shifters, namely a 5-bit digital phase shifter and a 360-degree continuously adjustable phase shifter, to illustrate the advantages of the present invention. The basic structure of this phase shifter consists of a waveguide and a solid semiconductor plasma unit. The 5-bit phase shifter is divided into 5 phase shift segments, each part is independent of each other, and the phase shift amount of each phase shift segment is fixed at 11.25°, 22.5°, 45°, 90° and 180°, respectively. The required phase is controlled by their mutual combination. At 36GHz, the simulated phase accuracy can be within 0.5°, and the in-band insertion loss flatness is within ±0.2dB. The 360-degree continuously adjustable phase shifter demonstrated by the present invention has a phase shift step of 1°, and the phase shift amount can be arbitrarily adjusted through external 360-way control, and the phase shift amount is an integer multiple of 1.

[0008] The BJ320 waveguide is a standard waveguide, corresponding to the frequency band used in the present invention. In addition, other forms of waveguides such as ridge waveguides and non-standard waveguides can also be used as RF transmission carriers;

[0009] The working principle of the 5-bit phase shifter is the same as that of the traditional digital phase shifter, which is to digitize the phase shift amount, perform switch control on the fixed phase shift amount module, and achieve the phase shift purpose through the corresponding combination;

[0010] The phase shift section refers to a waveguide structure composed of a group of solid semiconductor plasma units with a fixed phase shift amount, including a waveguide with a fixed length and a group of solid semiconductor plasma units with substantially the same length. A group of solid semiconductor plasma units in each phase shift section has two states: a phase shift state and a non-phase shift state. A group of solid semiconductor plasma units in each phase shift section is controlled by an independent switch.

[0011] The 360-degree continuously adjustable phase shifter refines the fixed phase shift amount to the required phase shift degree, such as 1°. At this time, the phase difference of each phase shift segment in the two states is the required phase shift degree, such as 1°. The phase shift amount of the phase shifter can be arbitrarily controlled through an independent driving circuit corresponding to each phase shift segment.

[0012] The beneficial effects of the present invention are:

[0013] Using traditional waveguide as carrier and combining with solid semiconductor plasma as a technical means, the phase shifting function of RF signal can be realized with extremely low insertion loss. Taking advantage of the high precision, simple control and no interference with RF signal of solid semiconductor plasma, it is entirely possible to design and manufacture a new type of phase shifter to replace the traditional phase shifter. Moreover, the technical route proposed by the present invention is flexible in design and can be designed in a variety of ways according to different situations. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0015] Figure 1 This is a structural diagram of the solid semiconductor plasma waveguide phase shifter of the present invention;

[0016] Figure 2 A side view of a waveguide phase shifter in a different form according to the present invention;

[0017] Figure 3 (a) is a structural diagram of a solid semiconductor plasma unit of the present invention;

[0018] Figure 3 (b) is a schematic diagram of a driving circuit of a solid semiconductor plasma unit according to the present invention;

[0019] Figure 4 This is a structural diagram of the 360-degree continuously adjustable phase shifter of the present invention;

[0020] Figure 5 A schematic diagram of the phase shift amount of a 5-bit digital phase shifter of the present invention;

[0021] Figure 6 It is a schematic diagram of insertion loss of a 5-bit digital phase shifter of the present invention;

[0022] Figure 7 Schematic diagram of the minimum phase shift of the 360-degree continuously adjustable phase shifter of the present invention. DETAILED DESCRIPTION

[0023] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0024] The operating frequency of the phase shifter designed in the embodiment of the present invention is 36 GHz.

[0025] Figure 1 It is one of the illustrative examples of the present invention, a 5-bit digital phase shifter 100, comprising the following two parts: a waveguide 101, the waveguide can be in any form, which is only shown in the figure for illustration; different numbers of solid semiconductor plasma units 200 are arranged on the inner wall of the waveguide, and the specific shape can be adjusted accordingly according to the inner wall structure of different waveguides. Figure 1 There are five phase shift segments of different lengths, each of which corresponds to a fixed phase shift amount, namely 11.25°, 22.5°, 45°, 90° and 180°. Each phase shift segment has a corresponding number of solid semiconductor plasma units, and each group of solid semiconductor plasma units is controlled by a corresponding drive circuit. Each phase shift segment is independent of each other and does not affect each other. The phase shift amount of the phase shifter is changed by different combinations, and the phase shift amount is an integer multiple of 11.25°.

[0026] Figure 2 The side views of phase shifters of three different waveguide forms are listed: 1011 is a side view of a conventional rectangular waveguide, 1012 is a side view of a single-ridge waveguide, and 1013 is a side view of a double-ridge waveguide. In 1011, 1012, and 1013, solid semiconductor plasmas are placed on the narrow inner walls on both sides of the waveguide.

[0027] Figure 3 (a) is a schematic diagram of the structure of the solid semiconductor plasma unit 200 used in the present invention: each solid semiconductor plasma unit 200 includes a SPIN diode, an oxide layer 206 and a dielectric substrate 205 sequentially arranged at the bottom of the SPIN diode, wherein the dielectric substrate 205 can be silicon, or glass, sapphire, silicon carbide and other flat or curved dielectric substrates; the SPIN diode is arranged on the surface of the solid semiconductor plasma unit 200, and is composed of an intrinsic layer 202, a P + Layer 203 and N + The SPIN diode adopts a lateral structure, the intrinsic layer is completely exposed to the upper part of the oxide layer 206, the P + Layer and the N + The layers are respectively arranged on the upper part of both sides of the intrinsic layer 202;+ Layer 203 and the N + Metal contacts 201 are disposed on the upper portion of the layer 204 on a side away from the intrinsic layer.

[0028] When the solid semiconductor plasma unit 200 is placed on the inner wall of the waveguide, the dielectric substrate 205 is closely attached to the inner wall of the waveguide, and the SPIN diode is located at the outermost side.

[0029] A solid semiconductor plasma unit 200 has a length of 20-200 microns, a width of 100-900 microns, a thickness of 20-70 microns, and a width of 5-20 microns of a metal contact.

[0030] Figure 3 (b) is a group of solid semiconductor plasma units with a certain number (≥1) and their driving circuits. Each group of solid semiconductor plasma units has a control switch circuit 207 corresponding to each other through a wire 208 to connect to the P of each solid semiconductor plasma unit 200 in the group. + The metal contacts 201 of the layer 203 are connected, and the N + The metal contact 201 of layer 204 is connected to the power ground through the wire 209. When the control switch circuit 207 is turned on and outputs a driving voltage greater than 0V to the P of all semiconductor plasma units 200 in the group, + When the metal contact 201 of the layer 203 is closed, the semiconductor plasma unit group is in an open state (phase shift state); when the control switch circuit 207 is closed and outputs a voltage of 0V to the P of all semiconductor plasma units 200 of the group, + When the metal contact 201 of layer 203 is formed, the semiconductor plasma unit is in the off state (non-phase shift state). The control switch circuit 207, the wire 209, the wire 208 and other driving circuits are integrated with the solid semiconductor plasma unit 200 on the same dielectric substrate through semiconductor processes such as TFT. The switching time between the conducting and non-conducting states of the solid semiconductor plasma is less than 1 microsecond. The driving voltage of a solid semiconductor plasma unit 200 is ≥ 0.5V, and the driving current is 0.1-30mA.

[0031] Figure 4 301 is a waveguide, and each group of solid semiconductor plasma phase shifting segments 302 having the same number (≥1) of solid semiconductor plasma units 200 are evenly arranged on the narrow side inner wall of the waveguide. Each phase shifting segment is composed of Figure 3In addition to the 1° minimum step shown in the embodiment of the present invention, the minimum step and the total phase shift amount can be designed according to the actual accuracy requirements. For example, by controlling the number of solid semiconductor plasma units in each group in 302, the phase change can be theoretically achieved with a minimum step of 0.5° at 36 GHz.

[0032] Figure 5 The diagram shows the phase shift of a 5-bit digital phase shifter. It can be seen that the phase shift accuracy of each stage is within 0.5° at 36 GHz.

[0033] Figure 6 This is a schematic diagram of the insertion loss of a 5-bit digital phase shifter. The figure shows the loss of the phase shifter in different states under three phase shift amounts. The initial state in the figure is the non-phase shifted state. Compared with the phase shifted state, the loss is much lower, within 0.03dB. The loss is about 0.11dB in the 90° phase shift state. The loss is basically twice that in the maximum 180° state. When all phase shift segments of the entire 5-bit phase shifter are working, the loss is within 0.5dB. It can be seen that the phase shifter proposed by the present invention has a very low loss compared to the traditional phase shifter, and the insertion loss consistency in the entire band of 34GHz to 38GHz is maintained within ±0.2dB.

[0034] Figure 7 It is a schematic diagram of the phase shift amount when the 360-degree continuously adjustable phase shifter of the present invention is shifted in steps of 1°. It can be seen that the phase consistency between 34 GHz and 38 GHz is maintained within 0.2°.

[0035] From the above results, it can be seen that the solid semiconductor plasma waveguide phase shifter proposed in the present invention has many advantages such as low loss, flexible design, applicability to high frequency bands, and convenient and simple control.

[0036] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A plasma waveguide phase shifter for millimeter wave frequency band, characterized in that: include: A waveguide and a plurality of groups of solid semiconductor plasma units, wherein the solid semiconductor plasma units are all placed on the narrow side inner walls on both sides of the waveguide; Through the power-on treatment, the position of the solid semiconductor plasma unit is on the inner wall of the narrow side of the waveguide, which is equivalent to compressing the long side of the waveguide, so that the frequency of the electromagnetic wave propagating in the new fundamental mode will increase. The change of the fundamental mode leads to the difference in phase before and after power-on, achieving the purpose of phase shifting; Each of the solid semiconductor plasma units comprises: a SPIN diode, an oxide layer and a dielectric substrate sequentially arranged at the bottom of the SPIN diode, the dielectric substrate is closely attached to the inner wall of the waveguide, and the SPIN diode is located at the outermost side; The SPIN diode is arranged on the surface of the solid semiconductor plasma unit, and is composed of an intrinsic layer, a P+ layer and an N+ layer; the SPIN diode adopts a lateral structure, the intrinsic layer is completely exposed to the upper part of the oxide layer, and the P+ layer and the N+ layer are respectively arranged on the upper part of both sides of the intrinsic layer; Metal contacts are disposed on the upper portions of the P+ layer and the N+ layer on a side away from the intrinsic layer; The plasma waveguide phase shifter is a 5-bit digital phase shifter having 5 phase shift segments, and the phase shift amount of each phase shift segment is fixed at 11.25°, 22.5°, 45°, 90° and 180° respectively, and the required phase is controlled by the combination of them. The phase shift segment refers to a waveguide structure composed of a group of solid semiconductor plasma units with a fixed phase shift amount, including a waveguide with a fixed length and a group of solid semiconductor plasma units with substantially the same length. A group of solid semiconductor plasma units in each phase shift segment has two states: a phase shift state and a non-phase shift state, and a group of solid semiconductor plasma units in each phase shift segment is controlled by an independent switch; Alternatively, the plasma waveguide phase shifter is a 360-degree continuously adjustable phase shifter, which refines the fixed phase shift amount to a required phase shift degree, and the phase difference of each phase shift segment in two states is the required phase shift degree. The phase shift amount of the phase shifter can be arbitrarily controlled by an independent driving circuit corresponding to each phase shift segment.

2. The plasma waveguide phase shifter for millimeter wave frequency band according to claim 1, characterized in that: The waveguide is a standard waveguide, a ridge waveguide or a non-standard waveguide.

3. The plasma waveguide phase shifter for millimeter wave frequency band according to claim 1, characterized in that: The dielectric substrate is a flat or curved dielectric substrate made of silicon, or glass, sapphire, or silicon carbide.

4. The plasma waveguide phase shifter for millimeter wave frequency band according to claim 1, characterized in that: The length of each solid semiconductor plasma unit is 20-200 microns, the width is 100-900 microns, the thickness is 20-70 microns, and the width of the metal contact is 5-20 microns.

5. The plasma waveguide phase shifter for millimeter wave frequency band according to claim 1, characterized in that: Each group of solid semiconductor plasma units has a one-to-one corresponding control switch circuit, and the control switch circuit is connected to the metal contact of the P+ layer of each solid semiconductor plasma unit in the group through a wire, and the N+ layer and metal contact of all solid semiconductor plasma units in the group are connected to the power supply ground through a wire.

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