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Power handling capability of a tunable plasma-based multilayer absorber is studied using multiphysics analysis, then validated by experimental data. The proposed two-pole absorber is based on conductor-backed thickness customizable high-order bandpass frequency-selective surfaces (FSSs). Such technique allows simple integration of the tuning elements, while simultaneously providing the option to realize FSSs (including absorbers) with specific/desired thicknesses and transfer responses. Lossy magnetodielectric slabs, used to absorb electromagnetic (EM) energy in the $C$ -band, are added between the metallic layers. The lossy slabs are perforated to host discrete, electrically tunable, ceramic gas-encapsulating chambers (plasma-shells), enabling dynamic control of the absorption spectral band. To study the power handling capability of the proposed multilayered tunable absorber, dielectric and air breakdowns within the device are numerically emulated using EM simulation by quantifying the maximum field enhancement factor (MFEF). Furthermore, a comprehensive thermal analysis using a simulation method that couples EMs and heat transfer is performed for the absorber under high-power continuous microwave excitations. Since the heat generated within the absorber is a primary concern, the steady state as well as transient state temperature distributions have been evaluated for various incident power densities. The performance of the proposed absorber is validated for a prototype having a finite size of $13\times13$ cm2.

This article presents a comprehensive study on shorted dipole antennas aiming for low-cost radio frequency identification (RFID) reader applications. Starting from a low-profile shorted bowtie dipole antenna, it is found that by varying the shorting wall position, three different types of resonant antennas could be realized with different radiation features. A low-profile planar inverted F antenna (PIFA) -type dipole is obtained by moving the shorting wall toward the feeding, which exhibits a low resonance frequency without obvious back lobe radiation or sidelobes. When the shorting wall is placed in the middle of the radiating patch, a mushroom-type dipole antenna can be built. A zeroth-order mode is also observed. This structure differs from the magnetoelectric dipole due to a low-profile structure. Placing the wall toward the end of the dipole arm leads to a loop-type antenna with a broader beam and a reduced gain. It also shifts the resonance toward the higher frequency. Based on the PIFA- and mushroom-type structures, two circularly polarized antennas with crossed shorted dipoles are designed and investigated carefully. Finally, two optimized, compact, and low-cost RFID reader antennas based on simple metal stamping process and screws are designed, fabricated, and tested, showing an excellent RF reading range. This study demonstrates that for the shorted dipole antennas, miniaturization and bandwidth control can be achieved simultaneously. Particularly, for higher gain and smaller size, the shorting wall should be placed close to the feeding to suppress the loop mode. For omnidirectional radiation, the loop mode should be enhanced by moving the shorting wall close to the end of the dipole arm.

Each year, Cu is used in more than 60% of electrical applications due to its excellent electrical, thermal, and mechanical properties. Here, we report all-printed flexible conformal electronics con...

A stripline-based composite right/left-handed (CRLH) leaky-wave antenna (LWA) with a tapered aperture is designed for an increased effective aperture size. Experimental results show that the CRLH LWA is able to scan from −33° to 25.5° by sweeping the frequency from 76.75 GHz to 83 GHz, with a half-nower heamwidth (HPRW) of less than 5°.

This paper presents a new design method, based on composite right/left-handed (CRLH) transmission lines (TLs), to realize frequency scanning reflectarrays. The proposed technique enables continuous steering of the reflected beam toward both positive and negative elevation angles, by simply connecting customizable progressive phase advance/delay lines to the existing delay lines of a broadband reflectarray. This unique feature would otherwise not be possible using conventional right-handed delay lines due to impractical physical lengths and lack of control over the phase slope. A small prototype array of 4 × 3 elements operating at a center frequency of 2.5 GHz is designed, fabricated, and measured to demonstrate the frequency scanning enhancement provided by the CRLH TLs.

The capability of the capacitively loaded loop (CLL) metamaterial (MTM) superstrate to attenuate surface waves thereby reducing the back radiation of microstrip patch antennas is examined. To understand the surface wave suppression mechanism, theoretical approaches of a grounded dielectric slab waveguide is provided. Both theoretical and numerical analyses show that the proposed superstrate causes a drastic attenuation of surface wave propagation. To confirm the numerical simulations, the proposed antenna is fabricated and tested. The dimensions of the CLL-MTM covered patch antenna are 0.6λ × 0.8λ × 0.14λ. The radiated gain and efficiency are measured at 7.8 dB and 95%, respectively. Measurements show that the front-to-back ratio is enhanced by more than 12 dB. In comparison with the patch antenna without the CLL-MTM superstrate, the proposed antenna reduces the gain and efficiency by less than 0.1 dB and 2%, respectively.

This paper presents the design and experimental test of dielectric permittivity sensors based on negative-order-resonances (NOR), which is supported by composite-right-left-hand (CRLH) structures. The proposed type of sensors is realized using high quality ${Q}$ -factor CRLH substrate-integrated-waveguide (SIW) resonator. By using the first NOR, −1st mode, a significant level of miniaturization is obtained; and moreover, this mode presents higher sensitivity over the 0th and +1st modes. To validate the proposed concept, testing results for five liquid samples are presented.

This paper presents the feasibility of deploying a large-scale tunable absorber based on discrete plasma-shells. The proposed conductor-backed absorber is realized by integrating ceramic gas-encapsulating chambers (plasma-shells) and a closely coupled lossy resonant layer that also serves as a biasing electrode to sustain the plasma. Two topologies comprising lossy inductive or capacitive layers are investigated to realize tunable microwave absorbers. The plasma is sustained by a sinusoidal radio frequency (RF) voltage source coupled directly through the walls of the plasma-shells. These active frequency-selective absorbers are analyzed using a transmission line approach to provide the working principle and its frequency tuning capability. By varying the voltage of the sustainer, the plasma can be modeled as a lossy, variable, frequency-dependent inductor, providing a dynamic tuning response of the absorption spectral band. A prototype plasma-tuned absorber is fabricated and measured in a free space environment to validate the concept. A good agreement between the equivalent circuit model, full-wave electromagnetic simulation, and the measurement results is obtained.

The capability of a magnetodielectric superstrate to suppress the surface wave propagation is investigated. It is shown that the capacitively loaded loop (CLL) metamaterial (MTM) superstrate exhibits a high degree of surface wave attenuation. One of the important applications of such structure is to reduce the mutual coupling between the microstrip patch elements in array antennas. The results of numerical simulations show a significant reduction in the mutual coupling between the antenna elements. To verify and confirm the simulation results, a prototype of the CLL-MTM superstrate incorporating an array of rectangular patch antennas are fabricated and tested. The proposed two-element array antenna has a dimension of approximately $1.6\lambda \times 0.9\lambda \times 0.16\lambda $ while achieving a gain and an efficiency of 8.2 dB and 97%, respectively. Measurement shows the mutual coupling reduction of over 55 dB. The CLL-MTM superstrate provides the gain and efficiency almost the same of unloaded array antennas with 0.1 dB and 2% changes, respectively.

We report the design, fabrication, and characterization of PDMS encapsulated physically flexible (bendable, foldable) gallium-based liquid metal band-stop frequency selective surface. A band-stop frequency selective surface (FSS) with targeted operation in the X-band (7~11.2 GHz) was designed. Liquid metal was embedded in PDMS microfluidic channels replicated from a deep etched Si mold. Ultra-low pressure (5.75 x 10-6 Torr) vacuum at cryogenic temperatures (10 K) was employed for clean encapsulation of liquid metal. An array of 5 x 5 FSS has been fabricated. Characterization of the fabricated FSS was carried out in a waveguide environment. The S-parameter values of the simulated and measured band-stop FSS response showed an excellent agreement.

General anesthetics (GAs) may cause disruptions in brain development, and the effect of GA exposure in the setting of pre-existing neurodevelopmental disease is unknown. We tested the hypothesis that synaptic development is more vulnerable to GA-induced deficits in a mouse model of fragile X syndrome than in WT mice and asked whether they were related to the mTOR pathway, a signaling system implicated in both anesthesia toxicity and fragile X syndrome. Early postnatal WT and Fmr1-KO mice were exposed to isoflurane and brain slices were collected in adulthood. Primary neuron cultures isolated from WT and Fmr1-KO mice were exposed to isoflurane during development, in some cases treated with rapamycin, and processed for immunohistochemistry at maturity. Quantitative immunofluorescence microscopy was conducted for synaptic markers and markers of mTOR pathway activity. Isoflurane exposure caused reduction in Synpasin-1, PSD-95, and Gephyrin puncta that was significantly lower in Fmr1-KO mice than in WT mice. Similar results were found in cell culture, where synapse loss was ameliorated with rapamycin treatment. Early developmental exposure to isoflurane causes more profound synapse loss in Fmr1- KO than WT mice, and this effect is mediated by a pathologic increase in mTOR pathway activity.

A 4-way equal-split in-phase power divider/combiner with broadband characteristics is presented in this paper. The proposed design uses a modified Gysel structure to enable heatsinking and design flexibility of the isolation resistors, while extending the bandwidth using a broadbanding technique previously only realizable for the 2-way case. By adapting a multi-layer microstrip/stripline topology with vertical interconnects, an N-way solution suitable for integration with planar technology can be achieved. A 4-way power divider/combiner prototype operating in the S-band is designed and fabricated, exhibiting bandwidth of over 30%. The measured results of the prototype show good agreement with full-wave EM simulation.

A novel waveguide-to-stripline transition utilizing an electromagnetic bandgap (EBG) structure is presented. The proposed transition, which does not require vias or waveguide shorts, delivers a simpler implementation option and allows the stripline to be mounted directly to the flange of a waveguide. The EBG structure is added to suppress parallel plate mode propagation and to ensure the transition can maintain the desired performance when used with arbitrary board dimensions. A 1.0dB insertion loss from 10.6GHz to 11.5GHz and a 10dB return loss bandwidth of 8.1% are achieved and verified by measurement.

This paper presents a new method of gaining spatial resolution in continuous wave (CW) Doppler radars by using a vibrating antenna. Resolution of direction finding, though conventionally controlled through beam steering or other circuitry, is decoupled from the antenna and front-end circuitry by vibrating the antenna in a controlled fashion. It is shown that vibrating an antenna results in an induced Doppler shift, whereby the return from each spatial angle has a different Doppler frequency. This allows for smaller aperture antennas or antenna arrays to be used in place of larger aperture antennas or antenna arrays, thereby reducing the overall system's size and complexity. As a proof of concept, a single vibrating antenna radar is designed, fabricated, and tested in order to verify the angle finding capability for a single, as well as multiple targets. This method may also be expanded into two-dimensional detection by integrating a vibrating one-dimensional array.

A flexible, fluidically tunable, second-order bandpass frequency selective surface (FSS) operating in the X-band is presented in this paper. The proposed multilayer structure utilizes elastomeric microfluidic channels to enclose and allow precise movement of gallium-based liquid metal slugs, while preserving its mechanically flexible nature. The liquid metal slug tuning elements are integrated into two periodic Jerusalem cross layers, which are coupled together through a periodic square aperture layer. By pneumatically shifting the position of the liquid metal slugs, the capacitance between adjacent Jerusalem cross elements can be linearly tuned, with high precision, to shift the operating frequency range of the filter in real time. Full-wave simulation of the bandpass FSS is performed for three different liquid metal slug orientations to demonstrate the tunability of the design.

As communication systems demand compact size and multi-functionality, advanced antenna elements with radiative feature including frequency-tunability, multi-band functionality, and polarization-flexibility are highly sought after. This paper presents a novel antenna structure delivering abovementioned desirable features. The antenna is fabricated on a single printed circuit board and tuned using varactors. The simulated results correspond well with the measured results. The proposed antenna shows frequency tuning range from 1.54 GHz to 2 GHz at first radiation band. Second radiation appears at around 5.3 GHz. The antenna has a very compact size of around 0.1\ {\lambda_{\mathrm{g}}}^{2}$ and 0.7\ {\lambda_{\mathrm{g}}}^{2}$ at first and second radiation frequencies, respectively.

1D & 2D W-band frequency scanning metamaterial antenna and array are proposed in this paper. Unlike the traditional microstrip-based design [1], we hereby highlight a relatively lower cost/loss antenna solution to the W-band beam steering application using stripline-based composite right/left handed (CRLH) leaky wave antenna (LWA). Our proposed passive CRLH LWA element is able to deliver positive, zero, and negative phase progression from 76 GHz to 81 GHz, thereby ensuring the backward (−28°) to forward (23°) fan beam frequency scanning when CRLH unit cells are periodically cascaded to form a 1D CRLH LWA. To further broaden the frequency mapping range to the hemisphere, we have also realized a 2D CRLH LWA that can produce highly directive pencil-beam radiation patterns. A coverage area of about −10° to 10° by −28° to 23° in elevation angle along the two orthogonal planes with a maximum gain of 26.1 dBi is realized by the proposed 2D CRLH LWA. In-depth analysis and simulated validation of both 1D/2D designs in this paper confirm the aforementioned functionalities.

Acute myeloid leukemia (AML) is a disease of the hematopoietic system that remains a therapeutic challenge despite advances in our understanding of the underlying cancer biology over the past decade. Recent developments in molecular targeting have shown promising results in treating leukemia, paving the way for novel treatment strategies. The discovery of drugs that promote apoptosis in leukemic cells has translated to encouraging activity in clinical trials. B-cell lymphoma (BCL)-2 inhibition has been at the center of drug development efforts to target apoptosis in AML. Remarkable clinical success with venetoclax has revolutionized the ways we treat hematological malignancies. Several landmark trials have demonstrated the potent antitumor activity of venetoclax, and it is now frequently combined with traditional cytotoxic agents to treat AML. However, resistance to BCL-2 inhibition is emerging, and alternative strategies to address resistance mechanisms have become an important focus of research. A number of clinical trials are now underway to investigate a plurality of novel agents that were shown to overcome resistance to BCL-2 inhibition in preclinical models. Some of the most promising data come from studies on drugs that downregulate myeloid cell leukemia (MCL)-1, such as cyclin-dependent kinases (CDK) inhibitors. Furthermore, innovative approaches to target apoptosis via extrinsic pathways and p53 regulation have added new cytotoxic agents to the arsenal, including drugs that inhibit inhibitor of apoptosis protein (IAP) family proteins and murine double minute 2 (MDM2). This review provides a perspective on past and current treatment strategies harnessing various mechanisms of apoptosis to target AML and highlights some important promising treatment combinations in development.

Although B-cell acute lymphoblastic leukemia (B-ALL) is the most common malignancy in children and while highly curable, it remains a leading cause of cancer-related mortality. The outgrowth of tumor subclones carrying mutations in genes responsible for resistance to therapy has led to a Darwinian model of clonal selection. Previous work has indicated that alterations in the epigenome might contribute to clonal selection, yet the extent to which the chromatin state is altered under the selective pressures of therapy is unknown. To address this, we performed chromatin immunoprecipitation, gene expression analysis, and enhanced reduced representation bisulfite sequencing on a cohort of paired diagnosis and relapse samples from individual patients who all but one relapsed within 36 months of initial diagnosis. The chromatin state at diagnosis varied widely among patients, while the majority of peaks remained stable between diagnosis and relapse. Yet a significant fraction was either lost or newly gained, with some patients showing few differences and others showing massive changes of the epigenetic state. Evolution of the epigenome was associated with pathways previously linked to therapy resistance as well as novel candidate pathways through alterations in pyrimidine biosynthesis and downregulation of polycomb repressive complex 2 targets. Three novel, relapse-specific superenhancers were shared by a majority of patients including one associated with S100A8, the top upregulated gene seen at relapse in childhood B-ALL. Overall, our results support a role of the epigenome in clonal evolution and uncover new candidate pathways associated with relapse. Significance: This study suggests a major role for epigenetic mechanisms in driving clonal evolution in B-ALL and identifies novel pathways associated with drug resistance.

In this letter, a miniaturized microstrip resonant antenna (MRA) based on the active metamaterial resonator is presented. Unlike the passive composite right/left-handed (CRLH) resonators, the presented active metamaterial resonators are realized using the negative-resistance-enhanced CRLH transmission line that incorporates active circuits for loss compensation. The active circuit uses bipolar junction transfer in its inverted-common-collector configuration to provide a negative resistance for the proposed active MRA. The presented passive and active antennas both operate in the negative-first-order resonance mode and thus have reduced dimensions compared to the conventional planar MRAs. The integration of the active elements delivers higher radiation gain compared to the passive negative-order CRLH resonator antenna. The passive and active antennas were fabricated, and the measured results are presented to validate the concept.

The feasibility of realizing an adaptive absorber subject to high-power microwave/electromagnetic (EM) pulse is investigated. To achieve this goal, a passive absorber based on circuit analog topology is designed and then embedded with active components to enable tunability/adaptivity of the absorption bandwidth. This tuning mechanism can be achieved using discrete plasma shells embedded in a low-profile frequency selective surface-based absorber. The absorption center frequency and bandwidth can be tuned by controlling the plasma frequency. A systematic design guide is presented to explain the working principle of the proposed absorber. The proposed design is insensitive to the polarization, and the absorption bandwidth is enhanced by controlling two spectrally overlapped resonances. A full wave EM simulation is performed to present the performance of the proposed absorber. Finally, the peak power handling capability of the active absorber has been investigated.

This letter describes a planar ultrawideband Vivaldi antenna for base-station pattern diversity applications. It is designed to cover most of the cellular and LTE bands, a very wide frequency range from 0.7 to 2.7 GHz. It is formed by two adjacent Vivaldi tapered slots with a rotated angle of 29° between them. The antenna is miniaturized by sharing some common structure and cutting the noncritical board area. It is designed step by step from a single Vivaldi element with a microstrip line feeding to a dual-slot pattern diversity radiator with uniform radiation patterns. It is fabricated and tested inside a near-field chamber. The radiation performance, including both in-phase and 180° out-of-phase differential feeding cases, is verified by simulation as well as experiment. The measured results show good agreement with the simulation. It could be useful for base station and other smart array systems.

This paper presents a design guide for the implementation of thickness customizable high-order ( $N \ge 2$ ) bandpass frequency-selective surface (FSS). Admittance inverters are used to synthesize the filter response given desired characteristics such as filter type, center frequency, and bandwidth. The spatial inverter layers are essentially electromagnetic coupling interlayers that can be adjusted to customize the thickness of multilayered FSS without degrading the desired filter performance. A generalized equivalent circuit is used to provide physical insights of the proposed design. This synthesized technique can be adopted to deliver a versatile implementation capability of high-order FSS filters using various dielectric spacers with arbitrary thicknesses. Such a technique enables the realization of spatial filters with variable weight and size, while maintaining the desired filter response. To highlight its thickness controllability, a third-order bandpass FSS operating at the X-band (center frequency at $f_{0} = 10$ GHz) with $\approx 10$ % fractional bandwidth is synthesized in four different thickness configurations (electrical size varying from $\lambda _{0}$ /12 to $\lambda _{0}$ /6). The simulation results of all the four thickness customized configurations deliver the same filter response. To validate the proposed technique, two prototypes among the four design configurations are fabricated and measured in a free-space environment. Simulated and measured results show good agreement.

A planar 2-D antenna array capable of mapping a full-hemisphere space to frequencies around 6 GHz is presented. It was designed using composite right-/left-handed transmission lines for the series feed network as well as for the radiating elements, thus achieving size reduction and beam steering control simplification compared to other approaches. Stripline fabrication technology is utilized to eliminate the undesired feed network radiation. A via-less unit cell reduces sensitivity to via misplacement. The result is an antenna that can be used for radar or imaging applications with the appropriate transmit/receive circuitry. Validation is provided by pattern measurements and successful detection of reflective targets.

In this paper, series feed networks based on composite right/left-handed transmission line for dual-polarized frequency scanning phased array antenna are presented. The proposed all-passive feed networks provide unique frequency dispersion and adjustable current amplitude distribution, which enable continuous backward-to-forward beam scanning capability as well as the directivity, beamwidth, and sidelobe level controllability of the incorporated array antenna. The working mechanisms are demonstrated through broadband dual-polarized aperture-coupled antenna elements and series feed networks that support uniform/binomial current amplitude distributions. Backward-to-forward frequency beam scanning and wide range beam shaping capability for dual-polarization states of the proposed phased array are validated in both simulation and measurement.

Supporting wide-band circular polarization (CP) over broad bandwidths poses a significant challenge for patch antennas and arrays. In any CP antenna, not only must the antenna's impedance-matching requirements be met; the circularity of the radiated wave polarization must be considered as well [1]. The circularity can be defined by a wave?s axial ratio (AR), which describes the variation of the instantaneous electric field magnitude versus time. An AR of lower than 3 dB is usually sufficient to ensure good circularity, although many high-performance applications demand 1 dB or less. The difficulty is in the timing of the two polarizations created to form the CP wave. At microwave frequencies, even errors on the order of tens of picoseconds can dramatically worsen the circularity.

A compact and novel printed antenna for 2.4-GHz WLAN/Zigbee/Bluetooth applications is proposed in this letter. To extend the bandwidth, a strip mode and a slot mode are combined together, which generate a dual-mode response inside the radiating band. To miniaturize the overall size, the structure is folded in order to fully utilize the available antenna space. The antenna is fabricated on a 1-mm FR4 board and excited by an SMA connector using a short microstrip line. It achieves a –10-dB bandwidth of 5.09% with a compact size of 0.073 λ 0 × 0.052 λ 0 × 0.008 λ 0 (9.2 × 6.5 × 1 mm3) and an in-band radiation efficiency above 73%. It is small and low-profile, which can be fabricated at a low cost using the standard printed circuit board (PCB) process. It shows good radiation performance and therefore is suitable for applications in Internet of Things and smart home devices.

L-section matching circuits are used for various applications. Such circuits can be advanced to provide notch responses to suppress undesired spurious signals. The design guide that allows integration of notch responses in the L-section matching circuits is presented. With given impedance at the targeted matching frequency and notch frequencies, a matching circuit with the spurious signal suppressing notches can be simply designed based on the closed-form equations provided. A composite lowpass filter (LPF) based on the image parameter method is composed of two matching sections and two filter sections. Replacing conventional matching sections with the proposed L-section matching circuits, an LPF with spurious signal notches can be realised. The proposed matching circuit and filter with spurious suppression notches will bring an added dimension of design freedom for modern communication systems that demand stringent out-of-band requirements.

This paper presents a multilayer absorber based on the technique previously developed for the design of a thickness customizable high-order bandpass frequency selective surface (FSS). Lossy substrates are used to absorb the electromagnetic energy in the FSS backed by a ground plane. Such technique allows simple integration of the tuning elements, while simultaneously providing the design option to realize the absorber with specific/desired thicknesses. The lossy substrates are perforated to host discrete electrically tunable ceramic gas-encapsulating chambers (plasma-shells). These plasma-shells enable dynamic control of the absorption spectral band. To demonstrate the design flexibility and performance, a second order frequency selective absorber operating at the C-band (center frequency at f 0 = 6 GHz with 17% fractional bandwidth) is designed with different thickness configurations. Then the plasma-shells are strategically integrated in the design in order to control the location of both absorption resonant frequencies by applying different plasma frequencies. Full-wave electromagnetic simulations are carried out to validate the proposed concepts.

A novel quasi-Yagi antenna based on a magnetic-current-loop-induced electric dipole is presented in this paper. The design emulates the conventional quasi-Yagi antenna by introducing multiple parasitic planar dipole elements that function as directors. However, unlike conventional designs, the proposed antenna radiates a vertically polarized wave by employing virtual dipoles oriented perpendicular to the plane. This eliminates the restriction of positioning the antenna at the edge of the board, providing increased flexibility of integration with microstrip circuitry. The proposed topology is verified through full wave simulation using ANSYS HFSS for antennas consisting of one, two, and five dipole elements.

A passive, long range, wide angle, chipless radio-frequency identification (RFID) tag operating in the S-band is presented in this paper. The proposed design consists of a broadband Van Atta retrodirective array incorporating perfectly matched bandstop filters in its feeding network, to encode identifying information across the frequency spectrum in the reflected signal while tracking the direction of the reader. As a result we are able to obtain a low-cost, high performance, microwave version of barcode that is easy to implement. A prototype is fabricated and radar cross section (RCS) is measured across the frequency range for three different combinations of identifying bits, to validate both the tracking capability and the data encoding ability of the design.

A full-sphere frequency scanning array antenna based on passive dual-band composite right/left handed series (CRLH) series integrated feeding network is presented in the paper. The proposed antenna array can support full-sphere (elevation angle θ = 0o to 360o) frequency beam scanning, where each θ is mapped to a unique frequency value. The array is realized by combining the dual-sided antenna elements with dual-band CRLH feeding network. For the antenna elements, both the proximity and aperture coupling are used to feed the radiators placed on the opposite sides of the shared ground plane. Furthermore, the right-handed and left-handed sections of the CRLH transmission lines (TL) are individually designed to provide the dual-band dispersion engineering of the proposed feeding network. In summary, directive full-sphere frequency scanning can be realized using an all-passive compact single array design. The full-sphere frequency scanning capability (a minimum of 30o in each quadrant) of the proposed passive array antenna is validated both in simulation and measurement.

A compact third-order bandpass frequency selective surface (FSS) with high selectivity and wide spurious-suppression bandwidth characteristics is presented. The proposed multi-layer FSS filter operating in the C-band, is composed of three Jerusalem Cross (JC) periodic array layers coupled together through periodic square aperture layers. The wide rejection band is obtained by incorporating bandstop JC layers that are designed to suppress spurious responses. The analysis of the design based on its equivalent circuit model (ECM) shows that the proposed FSS design can be synthesized with inductively coupled bandpass resonators from filter theory. To demonstrate its superior response, the proposed third-order FSS is compared through full wave simulation with its counterpart [5], which uses complementary JC layers that behave as parallel LC bandpass resonators.

Tunable leaky wave antenna (LWA) based on bidirectional amplifier enhanced composite right/left handed transmission line (CRLH TL) is proposed in this paper. Phase offset and current amplitude distribution of the LWA can be individually controlled by manipulating the CRLH TL and the biasing voltage of the bidirectional amplifier, respectively. While the CRLH TL controlled phase offset dictates the beam scanning angle, the bidirectional amplifier allows radiation pattern tunability. The directivity, radiated power, and main beam width tunability are experimentally verified by comparing the radiation performance of the proposed LWA in OFF (0V) and ON (0.9V) states.

This paper presents a novel tri-orthogonal polarization antenna operating at 2.4 GHz with good prospective for WLAN and MIMO systems. The design is implemented by integrating dual polarized cross-slot antenna and zeroth-order resonant (ZOR) antenna. The total height of the antenna is 0.762 mm corresponding to 0.01λ g (where λ g is the guide wavelength at 2.4 GHz). Linear horizontal dual-polarization and vertical polarization radiation patterns are obtained by using cross-polarized slot antennas and ZOR array antenna respectively. The broadside gain provided by the slot radiation is 5.3 dBi while the azimuthal average gain of the ZOR antenna is about 1.2 dBi.

A dual-polarized frequency-scanning phased-array antenna based on composite right/left handed (CRLH) feed network is presented. The proposed feed network provides phase advance in addition to phase delay and allows uniform power distribution to each antenna element, thereby delivering high directivity frequency-scanning radiation beams that can scan the full-hemi-sphere. The working mechanism is presented through a broadband microstrip antenna. The orthogonally placed feed networks and coupling slots enable the dual-polarized (horizontal/vertical) operation of the proposed antenna array without compromising the high isolation between two feeding ports. Full space frequency-scanning capability for both polarization states are verified experimentally.

A half-mode hexagonal substrate integrated waveguides (HMHSIW) structure with the internal angle of 90 degrees is presented and then applied in realizing a low-profile, dual-band/tri-polarized antenna with three independent ports. Dual-band composite right/left-handed (CRLH) substrate integrated waveguide (SIW) antennas and zeroth order resonator (ZOR) SIW antennas are designed based on the proposed HMHSIW to efficiently integrate the antennas while ensuring overall side reduction and providing enhanced design freedom.

An active substrate integrated waveguide based dual-polarized directivity enhanced full-space scanning composite right/left handed leaky-wave antenna for polarimetric radar applications is proposed. The proposed antenna is realized by using reflection type amplifiers to compensate both radiation and material losses, thereby increasing the effective aperture dimension and directivity of the antenna without compromising all unique features of metamaterial leaky-wave antenna including full frequency-scanning (backfire-to-endfire) capability and bilateral operation. Bilateral operation is essential in radar applications to allow both transmitting and receiving operations. The proposed dual-polarized full frequency-scanning polarimetric radar antenna may be operated in either: 1) linear slant (+45° and −45°) polarization mode, 2) linear horizontal/vertical polarization mode, or 3) right/left-handed circular polarization mode. This paper demonstrates the operation of the proposed active antenna in horizontal/vertical polarization mode. The realized active antenna shows directivity enhancement compared to its all passive counterpart.

Background: The treatment paradigm of adult patients with acute lymphoblastic leukemia (ALL) is primarily derived from successful pediatric chemotherapy regimens. Pegasparagase (PEG) is a key component of pediatric therapy and is the backbone of cytotoxic ALL regimens. However, among the adult population the use of PEG has been limited by the difficulty in tolerating prolonged asparagine depletion. Hepatotoxicity is among the most common adverse events reported with the use of PEG, with grade 3/4 hepatotoxicity seen in 20% of young adults compared to 40-60% of older adults. Incorporating PEG into the treatment of ALL patients under 40 remains an accepted practice despite some studies that report up to 75% of patients have grade 3/4 adverse events as a result of asparagine depletion. In a study of 85 patients with ALL, 3-year overall survival (OS) was significantly different between patients older and younger than 35 (52% vs 83% p = 0.003). Whether this difference is due to PEG toxicity or to other factors remains to be determined. At NYU hospitals, PEG-containing protocols are frequently deployed to treat adult ALL. In our study, we sought to look at the difference in PEG toxicity and response rate (RR) in patients older and younger than 35 and whether these toxicities contributed to a delay in subsequent treatments and to a worse outcome. Methods: We conducted a retrospective chart review of patients older than 18 diagnosed with ALL or lymphoblastic lymphoma, who received at least 1 dose of PEG at our institution between 2014 and 2018. All patients received PEG as part of their first line treatment protocol. Our main objective was to compare the tolerability and toxicity profile of intravenous PEG in patients ≥35 years old versus Results: Out of a total of 50 patients, 23 were age ≥ 35 (46%). Mean age was 34.4 (Range: 18.9-63.1). The 2 groups shared similar distributions in gender, race, and Philadelphia chromosome (Ph) subtypes (Table 1). The older group received significantly less PEG, 5114.8 vs. 25353.7 units (p=0.0007) and 1.65 vs. 3.59 doses (p Conclusions: Patients aged ≥ 35 received significantly less PEG during their treatments but were more likely to develop severe grade 3-4 hepatotoxicity compared to their younger counterparts. The response rates were similar with comparable MRD negativity rates after induction regardless of total amount of PEG administered. However, relapse occurred more frequently in the older group, possibly resulting from more frequent delays in administering other chemotherapy agents due to PEG toxicity. Incorporation of PEG is important in the treatment of ALL but should be used with caution in patients ≥35 years old, and will likely require dose and schedule modifications. A larger prospective trial investigating adequate dosing and scheduling of PEG in this age group is warranted, specifically comparing delays in chemotherapy, relapse, and survival rates in regimens with and without PEG. Disclosures No relevant conflicts of interest to declare.

A retrodirective array (RDA) capable of retransmitting predictable polarization with respect to any received polarization state is presented. RDAs have the unique ability to scatter the received signal back to the interrogator without prior knowledge of the source location. In addition to this unique feature, the proposed system can receive any polarization and always retransmits the signal that is orthogonally polarized with respect to the received polarization state. This added feature helps to maintain a more stable communication link between the RDA and the interrogator by mitigating the polarization mismatch loss. The proposed system shows excellent retrodirectivity for various received linear and circular polarizations. © 2013 IEEE.

The λ/2 strip-resonator directional filter has good balance between compactness and robustness against manufacturing error. However, there have been difficulties in generalizing the strip-resonator directional filter to realize multipole filtering responses. This paper presents the theory, experiments, and improvement of a new structure of strip-resonator directional filter based on a band-reject filter. This new structure allows the realization of multipole responses and theoretically does not limit the types of filter responses. A three-pole elliptic directional filter prototype is studied thoroughly to show that its performance can be predicted accurately by a conventional filter structure. We also propose a modification of the delay-line part using composite right-/left-handed transmission line to improve the isolation. An isolation level of 30 dB is shown to be achieved consistently.