Positive-intrinsic-negative Diodes Research Articles

Multifunctional Spoof Plasmonic Transmission Line with Dynamically Switchable Modes

AbstractA multifunctional transmission line (TL) based on spoof surface plasmon polaritons (SSPPs) is proposed for dynamical switching features among bandpass, band‐stop, and dual‐band phase shifting functionalities. Different operating modes can be controlled in real‐time by changing the states of the Positive Intrinsic Negative (PIN) diodes synchronously. The dispersion properties of the spoof plasmonic unit cell and transmission characteristics of the tunable PIN‐diodes‐loaded spoof plasmonic TL are investigated to highlight the basic theory and method. A prototype of the proposed TL composed of five cascaded unit cells is fabricated and tested for proof‐of‐concept validation. In the ON state of the PIN diodes, the measured −3 dB transmission frequency bandwidth ranges from 3 to 8.1 GHz for the bandpass characteristic. In the OFF state, the measured −10 dB rejection band spans from 3.7 to 5.6 GHz for the bandstop characteristic. When the diodes are switched between ON and OFF states, the measured dual‐band phase shifts vary from 192° to 203° and 248° to 292° in the 3.1–3.4 GHz and 6.1–9.4 GHz frequency bands, respectively. The validated switchable features of the TL pave the way for applications of tunable SSPPs in large‐scale integrated circuits and smart wireless communication systems.

A reconfigurable multifunctional polarization converter based on active metasurface

In this paper, we report a reconfigurable multifunctional polarization converter (RMPC) based on positive-intrinsic-negative (PIN) diodes, enabling to achieve different functions in different bands and states. The simulations and experiments show that when the PIN diode is off, it acts as a broadband linear polarization (LP) converter at 9.12–15.93 GHz. Simultaneously, when the PIN diode is on, the LP incident wave is converted into a left-handed circular polarization wave at 8.69–11.41 GHz and a cross-polarization wave at 13.40–14.97 GHz, whereas full reflection is obtained at 12.05–12.54 GHz. The RMPC consists of two dielectric plates and three layers of metal copper plates. Finally, a sample was fabricated and measured, the simulated and experimental results were in good agreement. Compared with other works, the RMPC has more working states and wider operating frequency bands, which has an application potential in the field of radar stealth and satellite communication.

Design of programmable beam splitting metasurface

Metasurface has been applied as one critical platform for electromagnetic modulation devices. Here, a programmable metasurface loaded with positive-intrinsic negative (PIN) diodes is proposed to realize dynamic switching of arbitrary multi-beam. Furthermore, the multi-beam coding sequence is optimized by a genetic algorithm (GA) to achieve dual- to nine-beam with different scattering directions. As a proof of concept, a programmable metasurface prototype that operates around 8 GHz is designed and fabricated to be tested in far-field measurements. The beam splitter has been verified by theoretical analysis and numerical simulation to have a power efficiency of over 70%. In the measurement system, multi-beam splitting phenomena are obtained using DC control of the PIN diodes “on” and “off”, which is consistent with the simulation results. The proposed beam splitter can be designed with real-time multi-beam switching and intelligently provides coding sequences with multiple directive angles, thus providing potential benefits for next-generation antennas.

Reconfigurable Compact Quad-port MIMO Antennas for sub-6 GHz Applications

This paper presents compact quad-port frequency reconfigurable multi-input multi-output (MIMO) antennas for 5 G applications that operate at sub-6 GHz. The proposed design provides more isolation (>13 dB) and pattern diversity using four orthogonal radiating elements. C-shaped metal is used to extend the antenna's radiating elements by inserting one positive intrinsic negative diode (PIN) in the metal. The C-shaped metal and matching stub achieve frequency reconfigurability with a consistent radiation pattern. The PIN diode's switching characteristics allow the frequency to be shifted between two communication bands. One mode (diode ON) covers 2.5 and 5 GHz, while the second mode (diode OFF) covers another dual band of 3.5 and 5.7 GHz. Substrate dimensions are only 50 x 50 x1.6 mm3, making the proposed design compact. Antenna peaks at a gain of 4.18 dB and radiation efficiencies of 80 and 94% in the four frequency bands. The antenna design is appropriate for multi-functional wireless systems and cognitive radio applications since it spans frequency bands below 6 GHz and can be reconfigurable between wide and narrow bands.

One‐bit wideband reconfigurable reflectarray with stable beam‐scanning gain for X‐band application

AbstractA wideband and electrically reconfigurable reflectarray (RRA) is presented for X‐band application. The unit cell is composed of two heterogeneous resonators, that is, a split resonator ring and a metallic patch, and two positive‐intrinsic‐negative (PIN) diodes integrated between these two resonators. A bias circuit on the bottom layer is designed to achieve the switching of the two states via properly placing the PIN diodes on the resonators with minimal electric field. One‐bit phase quantization is obtained by switching two different resonant mode via controlling the ON or OFF state of two PIN diodes. The simulated results show that the proposed unit cell can achieve one‐bit phase quantization with 180° ± 20° and reflection coefficients of ‐1 dB from 9.5 to 10.8 GHz, corresponding relative bandwidth of 12.81%. In addition, a fully functional 12 × 12 RRA fed by a linearly polarized horn is theoretically designed, simulated, and fabricated. The measured results show that the main beam can be steered from −50° to +50° at operating frequency, for example, 10.1 GHz with 1.5 dB gain loss within the scanning range and 20.34% aperture efficiency. In addition, the measured average gain is about 17.5 dBi and 3 dB gain bandwidth is about 15.68% from 9.4 to 11 GHz. In virtue of wide bandwidth, stable radiation gain, and good beam scanning capability, the proposed RRA is promising for future wireless communication and radar.

A quad-port multiple-input-multiple-output system for underlay or interweave cognitive radio

<span lang="EN-US">This paper presents a four-element frequency reconfigurable antenna system that is novel in terms of gathering both underlay and interweave cognitive radio in a single multiple input, multiple output (MIMO) design. Built on a 50×38×0.8 mm3 Rogers RT/Duroid 5880 substrate, this system is constructed of two scanning elements to sense ultra-wide band (UWB) with controllable band notching capabilities and two elements act as communication antennas. Eighteen MIMO modes can be provided depending on the state of the five positive-intrinsic-negative (PIN) diodes in each sensing antenna and the four PIN diodes in each communication antenna. These include a scanning UWB mode, fourteen modes to notch WiMax/Cband/<a name="_Hlk120169348"></a>wireless local area network (WLAN)/Xband/ITU in single/dual/triple/quad band rejection states and three interweave modes where each targeting one of the regions of WiMax/Cband/WLAN. Simulated by CST v.10; results like input reflection coefficient and realized gain verify system's capability to work in each operation mode. Moreover, mutual coupling, envelope correlation coefficient and diversity gain all evidence the performance of the proposed system as a MIMO system. Results, simple and compact profile, wide and flexile range of MIMO operation modes in line with the novelty to handle both underlay and interweave cognitive radio all nominate this system as promising to fulfill the needs of modern wireless communications.</span>

A reconfigurable dual port antenna system for underlay/interweave cognitive radio

<span lang="EN-US">An antenna system that is reconfigurable in frequency is presented in this paper as a novel dual port design that serves both undelay and interweave cognitive radio. This 25×40×0.8 mm3 system is composed of two wide slot antennas: the first is designed as an ultra-wideband (UWB) antenna with controllable band rejection capabilities, while the second antenna is reconfigurable for communication purposes. Three slots are etched into the patch of the UWB antenna to obtain band notching in wireless local area network/Xband/International Telecommunication Union bands (WLAN/Xband/ITU) bands which can be controlled by a positive-intrinsic-negative (PIN) diode across each slot. The configuration states of these three diodes are all useable that produces seven band rejection modes plus the UWB operation mode. The second antenna is configured by five PIN diodes to operate either in Cband, WLAN or Xband regions which results in three interweave modes when setting the first antenna for UWB sensing. The design is simulated by computer simulation technology (CST) v.10. S21 results shows good isolation while input reflection coefficient and realized gain results prove system’s scanning, filtering and communication capabilities. This system is new that it gathers the undelay/interweave operation in a single design and when considering its large number of operation modes it looks adequate for many cognitive radio applications.</span>

Power Limiter with PIN Diode Embedded in Cavity to Minimize Parasitic Inductance

This letter introduces a power limiter that limits the input power to protect the receiver when a large power enters the radio frequency receiver. When the power limiter receives a large power signal, a positive-intrinsic-negative (PIN) diode is turned on to limit the input power by lowering the impedance. We analyzed the characteristics of the power limiter according to the method of connecting the PIN diode in parallel with the input and output transmission lines of the power limiter. By embedding a PIN diode into the cavity and minimizing the length of the wire, a power limiter was designed and implemented to minimize parasitic inductance. In the S-band, the proposed power limiter’s insertion loss was below 0.5 dB, and the reflection loss characteristics were below 15 dB. Furthermore, it achieved an output P1dB of 21.8 dBm at 3.5 GHz.

An X-Band Reflective Active Polarization Conversion Metasurface

In this paper, an active polarization conversion metasurface (APCM) operating in the X-band (8–12 GHz) is presented. Active unit cells consist of three metal layers and two substrate layers. Anisotropic metal patches, positive-intrinsic-negative (PIN) diodes, and bias lines are integrated into the surface layer to form a chiral structure. A simple and efficient polarization conversion function is realized in this designed structure. The operating mode is switched between linear-to-linear (LTL) polarization conversion and linear-to-circular (LTC) polarization conversion by switching the loaded PIN diode. In the LTL polarization conversion state, the polarization conversion ratio of APCM is over 90% in X-band. Reflected wave circular polarization axis ratio <3 dB in 8–12 GHz when in LTC state. The proposed structure is verified by experimental measurements.

Design and characterization of polarization reconfigurable heart shape monopole antenna for 2.4 GHz application

<span>This article represented a heart shape reconfigurable monopole antenna with polarization diversity. The proposed antenna is fed by a 50 Ω microstrip feed line that is printed on a flexible FR-4 (εr=4.4) substrate. The antenna comprises a ring-slot, a cross slot and four positive-intrinsic-negative (PIN) diodes that are soldered on ring slot. Four PIN diodes act as a switch and by controlling these PIN diodes effective current direction is changed hence four various states of polarization are achieved. Four states of polarization such as horizontal linear polarization (H-LP), vertical linear polarization (V-LP), right-hand circular polarization (RHCP) and left-hand circular polarization (LHCP) can be switched easily with the help of these PIN diodes and achieved an efficiency of more than 90%. Proposed antenna shows voltage standing wave ratio (VSWR)<2 at all working frequency and -10 dB reflection coefficients (RC) bandwidths (BW) (i.e., S11≤-10 dB) about 32.86% for linear polarization (LP) states while RHCP and LHCP states possess BW of about 31.61% and 31.67% respectively. It also shows axial ratio (AR) BW of 3.41% and 2.44% for RHCP and LHCP, respectively. Besides, the antenna has a well-suited omnidirectional pattern with a positive gain of all working frequency of interest where cross-polarization level is much lower than that of antenna gain.</span>

Ultraviolet-sensing metasurface for programmable electromagnetic scattering field manipulation by combining light control with a microwave field.

Combining digital information science with metasurface technology is critical for achieving arbitrary electromagnetic wave manipulation. However, there is a scarcity of contemporary scholarly studies on this subject. In this paper, we propose an Ultraviolet (UV) sensing metasurface for programmable electromagnetic scattering field manipulation by combining light control with a microwave field. The active sensing of UV light and the real-time reaction of the scattering are achieved by integrating four UV sensors on the metasurface. On the metasurface, a UV sensor ML8511 and a voltage driver module are coupled to control each row of the Positive-Intrinsic-Negative (PIN) diodes. Due to the light sensing capability of the UV sensor, the on or off state of the PIN diode integrated into the programmable metasurface can be switched efficiently through the change of light. When the incident wave changes, various discrete data are transmitted to the FPGA. Then the FPGA performs the corresponding voltage distribution to control the state of the PIN diode. Finally, different metasurface coding sequences are generated to realize different electromagnetic functions. As a result, the spatial distribution of sensing light by sensors can be used to determine the electromagnetic field and connect sensing optical information with the microwave field. The simulation and measured results show that this design is feasible. This work provides a dimension for electromagnetic waves modulation.

A phased array design using a novel pattern reconfigurable antenna element

A novel pattern reconfigurable patch antenna is proposed. For the proposed antenna, the surface of the radiation patch is vertical to the ground plane, and it can be considered as a one-dimensional wire antenna. By embedding two positive-intrinsicnegative diodes into the radiating patch, a pair of tilted beams can be generated in the E plane, and they are directed to θ = ± 30°; besides, a side lobe level of less than −15 dB is also obtained. The mechanism of generating the tilted beams is explained. Based on the pattern reconfigurable antenna, a 1 × 8 phased array is designed. Both measured and simulated results demonstrate that the phased array operated at 3.45 GHz can give a gain fluctuation of less than 1 dB when the beam is scanned from −70° to 70°, and a side lobe level of lower than −11 dB is realized in the scanning range from −60° to 60°. Details of antenna structures and array performances are presented.

Impact of the structure on the thermal burnout effect induced by microwave pulses of PIN limiter diodes

Positive-intrinsic-negative (PIN) limiters are widely used to protect sensitive components from leakage power itself and adjacent high-power injection. Being the core of a PIN limiter, the PIN diode is possible to be burnt out by the external microwave pulses. Here, using a parallel computing program for semiconductor multi-physics effects designed by ourselves, we studied the influence of the thickness of the I layer and the anode diameter of the PIN diode on the maximum temperature change curve of the PIN diode limiter. The damage threshold criterion in the numerical simulation was first studied by comparing experimental results with simulation results. Then, we determined the impact of the structure on the thermal burnout effect induced by microwave pulses of PIN limiter diodes.

Twelfth mode on-demand band notch UWB antenna for underlay cognitive radio

A wide-slot ultra-wideband (UWB) antenna with on-demand band rejection characteristics that can serve underlay cognitive radio is presented in this paper. This antenna is designed to work in twelve operation modes; one to cover the whole UWB while each of the rest modes excludes one or more of the ranges that are allocated for Worldwide Interoperability for Microwave Access (WiMax), C-band, wireless local area network (WLAN), X-band and International Telecommunication Union (ITU) in a single, dual, triple, quad or penta band rejection state. A spiral shape slot in the patch and three slots mainly based on half-circular structures in the ground plane are the means to create the desired frequency notches. A positive-intrinsic-negative (PIN) diode across each of these slots is used to enable/disable band(s) rejection process. Configuration of the proposed antenna to the desired mode of operation is decided by the state of its four PIN diodes. This work is simulated by computer simulation technology (CST) v.10. It’s S11, voltage-standing-wave-ratio (VSWR) and realized gain results when combined with antenna's 25x25x0.8 mm3 compact size and the large number of modes and states, all ensure its capability to eliminate or reduce the interference within the targeted bands and hence being suitable for the applications of underlay cognitive radio.

Sub-6 GHz Quad-Band Reconfigurable Antenna for 5G Cognitive Radio Applications

This article describes a quad-band frequency tunable antenna for 5G applications that operates in the sub-6 GHz frequency range. On the top side, a stubloaded square patch is printed on an inexpensive glass epoxy substrate, and on the opposite side, a C-shaped slot embedded into the partial ground plane. To achieve frequency reconfigurability with a consistent radiation pattern, the C-shaped slot and matching stub are used. The antenna is electronically frequency tunable by placing two positive intrinsic negative diodes (PIN) in the C-shaped slot and one PIN diode between the stub and feed line. The frequency is tunable between one ultra-wideband (UWB) and three communication bands based on the switching conditions of the PIN diodes. The proposed configuration is small, with a substrate dimension of 25×25×1 mm3. The antenna was fabricated, tested and found measurements result back up the simulation; it can switch between UWB (3.31.0-6.03 GHz) and three communication modes (3.31-4.32, 3.78- 4.98, 4.98-5.96 GHz). The antenna has peak gains of 1.91, 1.86, 2.0 and 2.0 dB, and radiation efficiencies of 80, 78, 83 and 86%, respectively, in the four frequency bands. The developed antenna is ideally suited for multi-functional wireless systems and cognitive radio applications since it covers the frequency bands below 6 GHz and is tunable between wide and narrow bands.

Multi-domain functional metasurface with selectivity of polarization in operation frequency and time

In this paper, we propose the design of a multi-domain functional metasurface (MDFM) that can achieve selectivity of polarization in operation frequency and time. The MDFM consists of a wire grating as the front layer, a frequency selective surface as the middle layer and an active orthogonal wire grating loaded with positive-intrinsic-negative (PIN) diodes as the back layer. The front wire grating serves as a polarization selective surface that only passes electromagnetic (EM) waves polarized perpendicular to the wire, whereas the middle frequency selective surfaces exerts a pass-band in the frequency-domain. To further obtain selectivity in the time-domain, another orthogonal wire grating loaded with PIN diodes is adopted to switch on/off the pass-band. Three functional layers are combined to integrate the three selective functions. To verify this design idea, a MDFM operating at 3.19 GHz was designed, with a total thickness about λ/11. A prototype was fabricated and measured to validate the design. The experimental results are in satisfactory agreement with the simulated ones. Due to multi-fold selectivity, the MDFM can achieve high rejection for unwanted signals and may find wide applications in areas such as wireless communication, EM compatibility and stealthy radomes.

Demonstration of Reconfigurable BPFs with Wide Tuning Bandwidth Range Using 3λ/4 Open- and λ/2 Short- Ended Stubs

In this paper, two implementations of reconfigurable bandwidth bandpass filters (BPFs) are demonstrated both operating at a fixed center frequency of 2.4 GHz. The proposed reconfigurable bandwidth filters are based on a square ring resonator loaded with λg/4 open-ended stubs that are permanently connected to the ring and converted to either 3λg/4 open-ended stubs or λg/2 short-ended stubs by means of positive-intrinsic-negative(PIN) diodes to implement two reconfigurable bandwidth states for each case. Due to the symmetrical nature of the design, even- and odd-mode analysis is used to derive the closed-form to describe the reconfigurable filters’ behavior. The switching between narrowband and wideband is achieved using PIN diodes. In the first implementation (λg/4 open-ended stubs to 3λg/4 open-ended stubs), a reconfigurable bandwidth bandpass filter is proposed where additional out-of-band transmission zeros are generated by integrating a λg/2 open-ended stub at the input port. In the second implementation (λg/4 open-ended stubs to λg/2 short-ended stubs), further improvement in the upper stopband is achieved by utilizing a pair of parallel coupled lines (PCLs) as feeding lines and a pair of λg/4 high impedance short-ended stubs implemented at the input and output ports. To verify the validity of the simulated results, the prototypes of the proposed reconfigurable filters were fabricated. For the first case, measured insertion loss is less than 1.8 dB with a switchable 3-dB fractional bandwidth (FBW) range from 28% to 54%. The measured results for the second case exhibit a low insertion loss of less than 1 dB and a 3-dB fractional bandwidth that can be switched from 34% to 75%, while the center frequency is kept constant at 2.4 GHz in both cases.

Damage accumulation mechanism in PIN diode limiters induced via multiple microwave pulses

Positive-intrinsic-negative (PIN) diodes are widely used as limiters to protect sensitive components from damage in radio frequency (RF) receiver systems and communication front-ends. However, PIN diode limiters can be burnt out due to the microwave pulses coupling through the front-end of RF receiver systems. The damage processes and mechanisms in PIN limiters are undoubtedly important topics. Here, the damage accumulation process in PIN limiters induced by external microwave pulses is studied via the injection experiments. The relationship between the degree of damage (i.e., insertion loss) in the limiters and number of the injected pulses is reported. The maximum temperature criterion for burnout in PIN limiters is theoretically predicted and experimentally verified not accurate, and it is further observed that the insertion loss of the PIN diode limiter changes significantly only if more energy is injected into the limiter via microwave pulses.

Planar beam‐switching dipole antenna

A new planar beam-switching dipole antenna is proposed in this study. It consists of a peanut-shaped dipole with folded slots and a pair of parasitic elements with two positive intrinsic-negative (PIN) diodes. The feeding structure is made up of a short microstrip line, which is excited by a differential signal. Based on the Yagi-Uda antenna, pattern reconfigurability is realised by changing the states of PIN diodes. The proposed antenna is simulated, fabricated and measured. Experimental results indicate that the proposed antenna obtains an impedance bandwidth for | S dd | <; -10 dB of 13.7% from 3.25 to 3.73 GHz. The average gain of the antenna is about 5.7 dBi, with the radiation efficiency up to 60%. The antenna realises the radiation bandwidth of 11.6% covering 3.25-3.65 GHz. The proposed antenna shows good performances, which makes it suitable for the applications of 5G communication system.

Isolation and frequency reconfigurable compact MIMO antenna for wireless local area network applications

In this study, to design a compact four-port multiple-input-multiple-output (MIMO) antenna for dual-band wireless local area network applications, both frequency and isolation between antennas are made as reconfigurable. Both antenna element and decoupling network shown in this study are designed using meander line concept. The frequency reconfigurable capability of the antenna is achieved by incorporating positive-intrinsic-negative (PIN) diodes in the meander line resonator. By making PIN diodes ON and OFF, four antenna elements switch their operating frequency in between 2.4-2.5 and 5.1-5.8 GHz bands. Isolation between the antenna elements also made as reconfigurable by placing PIN diodes in the decoupling network. In ON state, isolation is found in 2.4-2.5 GHz band, whereas in OFF state, isolation is achieved in 5.1-5.8 GHz band. Overall, in both the bands, excellent isolation (more than 15 dB) between the antenna elements has been achieved. The proposed antenna design is printed on the FR-4 substrate and its overall area is 38 × 38 mm 2 . Each antenna element is in polarisation diversity with the adjacent antenna element which makes the proposed design suitable for achieving good MIMO performance.