A terahertz self-oscillating source with an LED-like structure

Abstract

The present invention relates to a terahertz self-oscillating source with an LED-like structure. The PN junction die of an impact avalanche transit time diode (IMPATT) and a resonant cavity for generating terahertz signals are integrally designed and combined together through microelectronic processes. Necessary constant current source excitation ports and output interfaces are designed to form a terahertz self-oscillating signal source similar to the structure of a light-emitting diode (LED), and a terahertz band emission signal array can also be formed, which is used as the emission source or pump signal of active and passive detection systems. This technology can be used in fields such as terahertz target detection radars, active and passive imaging, and broadband communications.

Description

Technical Field

[0001] The present invention belongs to the technical field of terahertz applications in electronic information engineering, and relates to a method for generating terahertz signals and a device manufacturing process. Specifically, it integrates the PN junction die of a collision avalanche transit time diode (abbreviated as "avalanche diode", English abbreviation IMPATT) that can operate in the terahertz frequency band with a resonant cavity, combines them together through microelectronic processes, designs necessary constant current source excitation ports and output coupling interfaces, forms a terahertz self-oscillation signal source similar to the structure of a light-emitting diode (LED), or can form a terahertz frequency band emission signal array by multiple similar structures, and is used as the emission source or pump signal of active and passive detection systems. This technology can be used in fields such as terahertz target detection radars, active and passive imaging, and broadband communication. Background Art

[0002] The characteristics of IMPATT (avalanche diode) are that there are avalanche regions and drift regions inside due to different doping concentrations. When a reverse bias voltage is applied to the diode, impact ionization avalanche breakdown occurs, and the generated carriers (electrons and holes) transit through the drift region. Furthermore, phase delays are generated in these two processes, resulting in a negative resistance effect and a stable microwave oscillation signal output. The working principle of the IMPATT oscillator is to utilize the interaction between the two physical effects of carrier impact ionization and transit time in the device structure, and with the help of an external oscillation resonant cavity, a phase difference that can make the diode exhibit a negative resistance effect is generated between the voltage and current acting on the avalanche diode, resulting in a periodic and stable signal output, thereby constituting a self-oscillation source in the required frequency band.

[0003] According to the traditional oscillator design concept in the millimeter wave frequency band, the IMPATT oscillator has a simple structure and a large output power, and is the preferred solid-state oscillator in the terahertz frequency band. However, from the perspective of technical implementation, the cavities of terahertz frequency band IMPATT oscillators are generally made of brass or alloy aluminum materials. Since the cavity and waveguide sizes are generally below the millimeter level, as small as the micro-nano level, considering factors such as machining accuracy and surface roughness, it is very difficult for the formed cavity oscillation frequency to exceed 300 GHz, which can only meet the low-end requirements of the terahertz frequency band. Moreover, due to machining tolerances, the machining consistency is poor, the debugging difficulty is large, and it is difficult to achieve mass production. For higher-end frequency oscillators, due to size and accuracy reasons, they can hardly be realized through mechanically machined cavities, and other methods have to be found.

[0004] Another method for generating terahertz signals is optical downconversion. This method is difficult to reach the low terahertz frequency band, and the equipment is complex and large in volume, and the generated terahertz signal power is small, making it difficult to be used for active detection. Summary of the Invention

[0005] Technical Problems to be Solved

[0006] The technical problem to be solved by the present invention is to break through the limits of traditional machining dimensions and precision, realize an integrated self-oscillating source in the terahertz frequency band through microelectronic process means, simplify the method of generating terahertz signals, increase the oscillation frequency of the oscillating source, achieve the consistency and serialization of mass production, facilitate the formation of an emission array, and realize the generation mode of terahertz signals where a single device emits signals immediately upon being powered on.

[0007] Technical solution

[0008] A terahertz self-oscillating source with an LED-like structure, characterized by comprising a heat sink, an LED-like bonding wire, a resonant cavity, an output coupling port, a PN junction die of an IMPATT diode, a cover and a horn, a support, electrode pins, and a substrate (19); the PN junction die of the IMPATT diode and the resonant cavity are attached to the surface of the heat sink, the two poles of the PN junction die of the IMPATT diode are connected to the electrode pins and an external power supply through the LED-like bonding wire, and the substrate and the support are used for supporting the terahertz self-oscillating source structure and external connection; when the electrode pins are externally connected to a qualified power supply, the PN junction die generates an oscillation signal inside the resonant cavity, and the oscillation signal is radiated outward through the output coupling port, and the cover and the horn play a role in protecting the internal structure and directing the output signal.

[0009] The PN junction die of the IMPATT diode is fixedly attached to the surface of the heat sink through an adhesive.

[0010] A terahertz frequency band emission signal array composed of the terahertz self-oscillating source with the LED-like structure, characterized by comprising 6 terahertz self-oscillating sources with the LED-like structure.

[0011] Advantageous effects

[0012] The beneficial effects of a terahertz self-oscillating source with an LED-like structure proposed by the present invention compared with the prior art are as follows:

[0013] (1) The present invention forms a terahertz frequency band resonant cavity and a signal output structure by using microelectronic process technology, replaces the metal waveguide structure in a microwave and millimeter wave oscillator, increases the operating frequency of the oscillating source, reduces the debugging link, can realize real-time signal output upon being powered on, facilitates the generation of terahertz signals, and improves the consistency and operating stability of the device.

[0014] (2) Using the structure described in the present invention, a separate terahertz self-oscillating source can be formed, and it is also convenient to form a linear array or a planar array of terahertz emission sources, reducing transmission loss and improving energy utilization efficiency.

[0015] (3) The volume of the oscillating source is reduced, the feeding structure is simplified, and flexible layout can be carried out according to needs.

[0016] (4) The self-oscillating source facilitates system use, reducing processing and usage costs. Description of the Drawings

[0017] Figure 1 Typical structure of LED

[0018] Figure 2 Schematic diagram of the terahertz self-oscillating source structure

[0019] 1 - PCB, 2 - heat sink, 3 - bonding wire, 4 - electroluminescent chip, 5 - optical lens, 6 - adhesive, 7 - frame, 8 - external pin, 9 - pad, 11 - heat sink, 12 - bonding wire-like, 13 - resonant cavity, 14 - output coupling port, 15 - PN junction die, 16 - cover and flared opening, 17 - support, 18 - electrode pin, 19 - substrate. Detailed implementation manners

[0020] The present invention will be further described in combination with embodiments and the drawings:

[0021] The technical solution of the present invention is: on the basis of inheriting the existing IMPATT diode PN junction die formation process, applying the working mechanism of the IMPATT oscillator, referring to the typical structure of LED, adding a waveguide resonant cavity, an internal signal coupling mechanism and an output coupling port to ensure the spectral purity and stability of the generated signal, designing the size and input / output structure of the resonant cavity through software simulation, designing the specific steps and methods for realizing by microelectronic semiconductor processes, and performing preparation and verification to achieve mass production of a single oscillator or generating a target of an emission signal array.

[0022] First, introduce the typical structure of LED: LED is an electronic device that can convert electrical energy into light energy and has diode characteristics. Its structure is as Figure 1 shown. The electroluminescent chip 4 is fixed on the surface of the heat sink 2 for heat dissipation through the adhesive 6. The two poles of the chip 4 are connected to the electrodes of the external pin 8 and the pad 9 through the bonding wire 3. The printed circuit board PCB1 and the frame 7 play a role in connecting and supporting the LED. When the external pin 8 of the LED is externally connected to a qualified power supply, the electroluminescent chip 4 emits light, and the optical lens 5 plays a role in directional beam focusing of the optical signal.

[0023] The terahertz self-oscillating source involved in the present invention is used to directly convert electrical energy into terahertz-band electromagnetic waves. The internal electromagnetic oscillation is generated by using the negative resistance oscillation principle of the IMPATT diode. The schematic diagram of the specific scheme is as Figure 2 shown.

[0024] The PN junction die 15 of the IMPATT diode and the resonant cavity 13 are connected through a similar Figure 1The process method is attached to the surface of the heat sink 11. The two poles of the PN junction die 15 are connected to the electrode pins 18 and an external power supply through the bonding wire-like 12. The substrate 19 and the support 17 are used for the support of the terahertz self-oscillating source structure and external connection. When the electrode pin 18 is externally connected to a qualified power supply, the PN junction die 15 generates a stable oscillation signal inside the resonant cavity 13, and the oscillation signal can be radiated outward through the output coupling port 14. The cover and the horn 16 play a role in protecting the internal structure and directing the output signal.

[0025] The frequency of the output terahertz signal is determined by the resonant cavity 13 and the PN junction die 15. According to requirements, the resonant cavity 13 can be generated by semiconductor processes or implanted after being generated externally. When the structure and size of the resonant cavity 13 and the technical parameters of the PN junction die 15 meet the electromagnetic resonance conditions, oscillation can occur. The output power of the terahertz self-oscillating source is then determined by the external power supply and the output coupling port 14.

[0026] The size of the heat sink 11, the signal coupling method (electric field coupling or magnetic field coupling), the position of the output port, the size and shape of the bonding wire-like 12, the signal output direction, whether to use a horn or a lens, etc. can be determined according to the optimization results.

Claims

1. A terahertz self-oscillating source of a LED-like structure, characterized in that It includes a heat sink body (11), a bonding wire-like component (12), a resonant cavity (13), an output coupling port (14), a PN junction die of an IMPATT diode (15), a cover and a horn mouth (16), a support body (17), electrode pins (18), and a substrate (19); the PN junction die (15) of the IMPATT diode and the resonant cavity (13) are attached to the surface of the heat sink body (11), and the two poles of the PN junction die (15) of the IMPATT diode are connected to the electrode pins (18) and an external power supply through the bonding wire-like component (12), and the substrate (19) and the support body (17) are used for supporting the terahertz self-oscillating source structure and external connection; when the electrode pins (18) are externally connected to a qualified power supply, the PN junction die (15) generates an oscillation signal inside the resonant cavity (13), and the oscillation signal is radiated outward through the output coupling port (14), and the cover and the horn mouth (16) play a role in protecting the internal structure and directing the output signal; the frequency of the output terahertz signal is determined by the resonant cavity (13) and the PN junction die (15); the resonant cavity (13) is generated by semiconductor processes or implanted after being externally generated, and oscillation can occur when the structure and size of the resonant cavity (13) and the technical parameters of the PN junction die (15) meet the electromagnetic resonance conditions, and the output power of the terahertz self-oscillating source is determined by the external power supply and the output coupling port (14); On the basis of inheriting the existing process for forming the PN junction die of the IMPATT diode, the working mechanism of the IMPATT oscillator is used to add a waveguide resonant cavity, an internal signal coupling mechanism, and an output coupling port to ensure the spectral purity and stability of the generated signal.

2. The terahertz self-oscillating source of a kind of LED structure according to claim 1, characterized in that The PN junction die (15) of the IMPATT diode is fixedly attached to the surface of the heat sink body (11) through an adhesive.

3. A terahertz frequency band emission signal array composed of the terahertz self-oscillating source with the LED-like structure described in claim 1, characterized in that It includes 6 terahertz self-oscillating sources in the structure of a LED-like.

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