A pattern-reconfigurable flexible textile antenna covering the 2.45 GHz Industrial, Scientific and Medical (ISM) band is presented. The design utilizes RF-switch Integrated Circuits (ICs) packaged ...into reconfiguration modules as switchable vias to change between the omnidirectional and broadside radiation modes of a center-shorted patch. Analytical models to calculate the resonance frequency of each mode are developed to give more physical insights into the mode resonance and assist the design optimization. An antenna prototype is experimentally characterized to further validate the concept and analysis of the proposed antenna structure. The stable performance under on-body environment and various bending test conditions demonstrates the antenna operation in wearable scenarios.
Recently, two-dimensional (2D) atomic sheets have inspired new ideas in nanoscience including topologically protected charge transport, , spatially separated excitons, and strongly anisotropic heat ...transport. Here, we report the intriguing observation of stable nonvolatile resistance switching (NVRS) in single-layer atomic sheets sandwiched between metal electrodes. NVRS is observed in the prototypical semiconducting (MX2, M = Mo, W; and X = S, Se) transitional metal dichalcogenides (TMDs), which alludes to the universality of this phenomenon in TMD monolayers and offers forming-free switching. This observation of NVRS phenomenon, widely attributed to ionic diffusion, filament, and interfacial redox in bulk oxides and electrolytes, − inspires new studies on defects, ion transport, and energetics at the sharp interfaces between atomically thin sheets and conducting electrodes. Our findings overturn the contemporary thinking that nonvolatile switching is not scalable to subnanometre owing to leakage currents. Emerging device concepts in nonvolatile flexible memory fabrics, and brain-inspired (neuromorphic) computing could benefit substantially from the wide 2D materials design space. A new major application, zero-static power radio frequency (RF) switching, is demonstrated with a monolayer switch operating to 50 GHz.
This article presents a four-element phased-array transceiver (TRX) front-end for millimeter-wave (mm-Wave) 5G new radio (NR). The effects of amplitude-to-phase (AM-PM) and amplitude-to-amplitude ...(AM-AM) distortions on error vector magnitude (EVM) are detailed. A three-stage highly linear wideband class-AB power amplifier (PA) is described, mitigating AM-PM and AM-AM distortions without degrading other performances. A matching network embedded transmitting/receiving (T/R) switch is proposed to support time division duplex (TDD). With the proposed technique, RF switch insertion losses are reduced in both transmitter (TX) and receiving (RX) modes. In each TRX element, phase and gain controls are achieved by a 6-bit vector-modulated phase shifter (VMPS) with a phase tuning range of 360° and a 6-bit attenuator with a gain tuning range of 31.5 dB, respectively. Fabricated in 65-nm bulk CMOS, the proposed packaged TRX demonstrates the measured peak gains of 25.5/14.2 dB with the gain ripples of less than 2.5/1.9 dB across 24-29.5 GHz in the TX/RX mode. The measured peak <inline-formula> <tex-math notation="LaTeX">P_{\text {1 dB}} </tex-math></inline-formula> is 17.6 dBm with a power added efficiency (PAE) of 20.4%. The measured minimum noise figure (NF) is 4.3 dB. The TRX achieves an output power of 7.9-8.9 dBm and an EVM of −25 dB with 8 <inline-formula> <tex-math notation="LaTeX">\times </tex-math></inline-formula> 100-MHz 5G NR frequency range 2 (FR2) orthogonal frequency division multiplexing (OFDM) 64-quadrature amplitude modulation (QAM) signals across 24-29.5 GHz, covering 3rd generation partnership project (3GPP) 5G NR FR2 operating bands (i.e., n257, n258, and n261) around 26 GHz.
A frequency-reconfigurable SP4T switch is presented, in which <inline-formula> <tex-math notation="LaTeX">{R}_{\text {ON}} \times {C}_{\text {OFF}} </tex-math></inline-formula> characteristics of ...switch transistors are enhanced with plaid metal transistors and forward body biasing. Plaid metal transistors (PMT) with forward body bias (FBB) are used for all of the transistors to enhance the FoM. The plaid patterned metal accesses of a transistor for the source and drain decrease the extrinsic resistance and capacitance. FBB increases the overdrive voltage of a transistor and decreases the on-resistance. The SP4T switch includes main switch matrices that route an input signal to four-outputs, a switched inductor (SI) network, and a mode-selection switch. The SI network connected through the mode-selection switch resonates out the off-capacitances of the main switch matrices at RF in the RF mode. The SP4T switch operates without the SI network in DC mode. The SP4T switch is implemented in a 28-nm FDSOI CMOS process. The core area occupies 0.2 mm 2 . The switch shows less than 2 dB insertion loss from DC to 4.4 GHz in the DC mode and from 4.4 to 5.3 GHz in the RF mode, where isolations are more than 16.8 dB and 18 dB, respectively.
This paper describes Ka-band inductor-shared RF switches and their applications to a 35.2-ps 6-bit true-time-delay (TTD) switched-line (SL) phase shifter (PS). The inductor-shared RF switches share ...an inductor to match the input and output (I/O) ports of different states, which are realized with a switched inductor for SP<inline-formula> <tex-math notation="LaTeX">{n}\text{T} </tex-math></inline-formula> case and with a shared matching network for DP<inline-formula> <tex-math notation="LaTeX">{n}\text{T} </tex-math></inline-formula> case. The switches are applied to controlling most significant 3 bits of the proposed TTD SL PS. The delay lines and reference lines of the PS are implemented with microstrip lines and inverted microstrip lines in the same space, respectively. The dual-side microstrip lines allow it to have not only a small size but also compensation of the loss difference between the signal lines with different lengths. The least significant 3 bits are implemented with the modified structure of the SL PS, which reduces the size further by replacing a reference line by a series switch. The test chip is fabricated in a 65-nm CMOS process. It operates in the range of 20-30 GHz occupying a 0.18 mm 2 core size. Its measured insertion loss and IP1dB are 11 dB and 6.5 dBm at 28 GHz, respectively. The measured gain error and rms delay error are less than 2 dB and 0.7 ps at operation frequencies.
Utilizing the 0.25 μm GaN HEMT process, a high‐isolation single pole double throw (SPDT) RF switch has been meticulously designed for the X‐band. The circuit topology employs a series‐shunt ...configuration to prevent signal leakage, thereby enhancing chip isolation. By incorporating series transistors and shunt inductors, LC resonance is achieved, significantly boosting isolation performance. To optimize port matching and ensure both heightened isolation and minimized insertion loss, inductors are strategically integrated into each port. The inclusion of these lumped inductors contributes significantly to reducing the chip's footprint. Die measurement results demonstrate that across the 8–12 GHz frequency spectrum, insertion loss remains below 1.1 dB, with isolation exceeding 36 dB. Remarkably, at 10.5 GHz, isolation peaks at an impressive 52 dB. Moreover, return loss surpasses 12 dB, and the 0.1 dB compression point input power stands at 43.5 dBm, all achieved within a compact chip area of only 1 mm2.
The GeTe phase-change RF switch with Ag conductive filament (CF) as heater is fabricated. The Ag CF as heater can effectively reduce the energy consumption of the switch. In particular, the set ...energy consumption is as low as 19.2 nJ to set the switch. In durability test, the resistance ratio exceeds three orders of magnitude and remains almost constant over 1000 cycles. The insertion loss of the phase-change RF switch based on GeTe is less than 0.8 dB and the isolation is greater than 20 dB up to 67 GHz. The cut-off frequency of the switch is as high as 15 THz. This work demonstrates that the modulated CF can be used as the heater for phase change material (PCM), providing a new micro directly heated structure for low energy consumption phase-change RF switch.
This article presents an approach to monolithically implement radio-frequency (RF) phase change material (PCM) germanium telluride (GeTe) T-type switch as a switching unit cell for millimeter-wave ...(mmWave) redundancy switch matrix applications. The miniature T-type switch demonstrates three states of operation, including one crossover state and two turn states. A seven-layer microfabrication process, including an additional conductive layer to reduce the RC time constant due to the bias network routing, is developed and optimized to fabricate the multiport RF devices. A 4×6 PCM-based redundancy switch matrix is developed by monolithically integrating four T-type switches in the cascade configuration. Thermal crosstalk in PCM switches is experimentally investigated using submicrometer spatial resolution transient thermal imaging. The presented T-type switch has the device periphery of 0.55 mm × 0.55 mm, while the overall integrated PCM redundancy switch matrix is fabricated with a device footprint of 0.88 mm × 1.1 mm. The measured results of the T-type switches demonstrate an excellent RF performance with lower than 1.6 dB insertion loss, better than 20 dB return loss, and higher than 20 dB isolation in all states from dc-67 GHz. The redundancy switch matrix exhibits an insertion loss less than 3 dB, return loss better than 14 dB, and isolation higher than 20 dB from dc-60 GHz. To the best of our knowledge, this is the first implementation of a PCM-based redundancy switch matrix.
In this communication, a 9-ring time-modulated concentric circular antenna array (TMCCAA) with isotropic elements has been studied based on an evolutionary optimization algorithm called cat swarm ...optimization (CSO) for the reduction of side lobe level (SLL) and improvement in the Directivity, simultaneously. The comparative case studies as Case-1 and Case-2 are made with three control parameters like interelement spacing in rings, interring radii, and the switching "ON" times of rings with the help of same algorithm. Experimental results show a considerable SLL reduction with respect to the uniformly excited case. The numerical results show Case-2 outperforms Case-1 with respect to SLL and Directivity. Apart from this, the powers radiated at the center/fundamental frequency and the first two sideband frequencies, and dynamic efficiency have been computed. It has been observed that as the sideband frequency increases, both the powers radiated by harmonic frequencies and sideband levels (SBLs) decrease.
In this communication, a low-cost, single-pole double-throw (SPDT) filtering radio frequency (RF) switch based on coupled resonators is proposed and utilized in a novel pattern reconfigurable antenna ...design. The proposed filtering switch employs two second-order quarter-wavelength microstrip resonant structures which can be controlled by p-i-n diodes, respectively. Compared with traditional switches based on p-i-n diode, this filtering switch can not only improve the RF response but also suppress the high-order harmonic, when it is used with an antenna. Then, a low-profile dual-port broadside/conical dual-mode antenna is proposed by embedding a slotted substrate integrated waveguide (SIW) cavity in the middle of a patch antenna. The slotted cavity is to realize the radiation in the broadside whereas the patch is fed by two probes in-phase to realize the conical radiation. Finally, the filtering switch and the dual-mode antenna are combined to realize the pattern reconfigurable antenna. By controlling the states of the p-i-n diodes, broadside and conical radiation patterns can be easily switched. The concept of switch-based pattern reconfigurable antenna is prototyped and experimentally verified. Measured results agree with the simulations, demonstrating a promising solution for pattern reconfigurable antenna designs.
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