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This communication presents a circular-polarized (CP) reconfigurable grating antenna for low-cost millimeter-wave beam steering. A CP grating array is introduced. Using an inertialess mechanical movement, the grating design can be reconfigured along the surface of a dielectric image line, allowing a directive CP beam to steer across a wide range of angles. Over 43[degree] of beam steering is achieved at 32.5 GHz with axial ratio less than 1 dB across the entire scan range. Measured performance agrees well with theory. These results are inherently scalable to higher millimeter-wave frequencies and should have numerous uses in emerging millimeter-wave satellite communications applications and other related systems for mobile communications and radar. Index Terms--Beam steering, circular polarization, gratings, millimeter-wave antenna arrays, reconfigurable antennas.

This paper presents a reconfigurable dual-beam grating antenna for low-cost millimeter-wave beam steering. Experimental results indicate that this multibeam approach provides over [+ or -] 50[degrees] beam steering at fixed frequencies across the entire 35 to 40 GHz band, with excellent radiation patterns maintained across the scans. An approximate analysis developed for the reconfigurable antenna closely predicts the observed scan angles and main beam radiation patterns across the complete range of scan states. These results should have numerous applications in millimeter-wave beam-steering technology. Index Terms--Beam steering, gratings, millimeter-wave antenna arrays, multibeam antennas, scanning antennas.

This paper introduces a novel, broadband, low-cost technique for beam steering at millimeter-wave frequencies using a moveable grating film fed by dielectric image line. An excellent radiation pattern is maintained over wide scan angles across the 30-40 GHz range, with up to 53[degrees] scanning reported at 35 GHz. Theoretical calculations closely predict the observed scan angle across the entire range of measurement. Index Terms--Beam steering, gratings, leaky-wave antennas, millimeter-wave antenna arrays, scanning antennas.

This paper presents a novel phased-array antenna system with multifrequency, full-duplex operation, and wide-beam scanning. The system consists of a wideband power divider, a low-loss and low-cost multiline phase shifter controlled by dual piezoelectric transducers (PETs) (1), a four-channel multiplexer, microwave monolithic integrated circuit (MMIC) amplifiers, and a stripline-fed Vivaldi antenna array. The multiline PET phase shifter has a low perturbation loss of less than 2 dB and a total loss of less than 4 dB up to 40 GHz, with a maximum phase shift of 650[degrees]. Using dual-aligned PETs for bidirectional phase shifting results in wide scan angles of 38.6[degrees], 37.6[degrees], 43[degrees], and 40[degrees] for the four channels at 10, 12, 19, and 21 GHz, respectively. The four-channel diplexer demonstrates low insertion loss with high isolation between channels. The new multifrequency phased-array system provides wide-beam scanning and full-duplex capability using a simple, low-cost architecture. The system can be used for applications in mobile satellite communications. Index Terms--Microwave monolithic integrated circuit (MMIC), multiplexer, phase shifter, phased array, piezoelectric transducer (PET), Vivaldi.

This paper summarizes and compares several recently developed techniques for beam steering without the use of conventional ferrite or solid-state phase shifters. Three methods are presented: a microstrip patch antenna array fed by a dielectric image line (DIL) controlled by a reflector plate, a multimicrostrip line fed Vivaldi antenna array controlled by piezoelectric transducers (PETs) (1) and a movable grating film fed by dielectric image line. (2) Both theoretical analyses and experimental measurements have been carried out. The measurement results agree very well with the predictions. These new techniques have many advantages, including low cost, broad bandwidth, low loss, wide scan angle, and simplicity. These low-cost beam-steering techniques should have many applications in microwave and millimeter-wave commercial systems. Index Terms--Beam steering, image line, phased array, piezoelectric transducer (PET).

This paper presents novel low-cost beam-steering techniques using microstrip patch antenna arrays fed by dielectric image lines (DIL's). Two approaches are designed and used. The first, DIL's without reflector plate, are used for feeding microstrip patch antenna arrays. Antenna array radiation beams are scanned when the operating frequency sweeps. The second, a dielectric image line with a movable reflector plate (DILWRP), is developed. The beam direction of the antenna array is controlled and steered by changing the perturbation distance between DIL and movable reflector plate at a given operating frequency. Both types of patch antenna array structures are simple, low cost, easily fabricated, stable, and reliable. Eight-element patch antenna arrays fed by DIL and DILWRP have been designed, fabricated, and tested. Experiments show good performance and results. Measurement results of scanning angles agree well with theoretical predictions. Index Terms - Beam steering, microstrip arrays.

This paper reports novel beam-control methods which have the potential of low cost and simplicity. The beam direction of the antenna array is controlled by changing the distance between the perturbed dielectric image line (DIL) and a movable reflector plate. A rigorous hybrid-mode theoretical analysis is developed for calculating the dispersion of propagation constants in DIL's without or with the movable reflector plate and, then, for designing beam-control patch-antenna arrays. Experimental results of scanning angles agree well with theoretical predictions at Ka-band frequencies. Index Terms - Beam steering, dielectric image line, millimeter wave, patch antenna.

This paper presents new tunable phase shifters using perturbed dielectric image lines (DIL's). The propagation constant in the DIL was perturbed by a movable metal reflector plate installed in parallel with the ground plane of the DIL. The phase shift was thus controlled and adjusted by varying the perturbation spacing between the DIL and movable reflector plate at a given operating frequency. A rigorous hybrid-mode analysis was used for calculating the dispersion of propagation constants in the perturbed DIL, and then for designing tunable phase shifters. Ka-band tunable phase shifters have been designed, fabricated, and tested. Measurement results agree well with theoretical predictions. The device is especially useful for millimeter-wave applications where traditional phase shifters are lossy. Index Terms - Dielectric image lines, millimeter waves, tunable phase shifters.

This paper presents the analysis and design of aperture-coupled microstrip patch antennas and arrays fed by an dielectric image line. A theory based on the cavity model of the microstrip patch antenna and the change in the modal voltage of the image line at the aperture was developed to analyze the single element aperture-coupled microstrip patch antenna. The theory developed was combined with the array theory to design linear traveling wave arrays at X-band and Ka-band frequencies. The required taper in the excitations of the individual patches of the array was achieved by varying the aperture dimensions. Experiments show very good results for the antennas and the arrays.

Low-loss bandpass filters consisting of Fabry--Perot resonators excited by slots which couple to higher order resonator modes are demonstrated. For close reflector spacings, the slots efficiently couple power from rectangular waveguide to the [TEM.sub.400] and [TEM.sub.300] modes of the resonator. At Ka-band the filters have insertion losses less than 1 dB in general and less than 0.5 dB in some cases. The unloaded Q values of the filters range from 1500 to 3000. The filters are mechanically tunable over a 25% bandwidth.

Overexpression of p68 has been reported in various types of cancer. However, little study has been conducted on the expression and role of p68 in cervical cancer. Therefore, the present study focuses on the role of p68 in cervical cancer cells, which may elucidate its potential mechanism of cervical cancer progression and shed light on the precision medical treatment of cervical cancer. Firstly, the expression of p68 was analyzed using reverse transcription-quantitative polymerase chain reaction and western blot analysis. The changes to cell morphology were observed using an inverted microscope (XDS-500D; Shanghai Caikon Optical Instrument Co., Ltd., Shanghai, China). Cell migration was determined using an in vitro scratch assay. The present study demonstrated that the mRNA and protein levels of p68 were significantly enhanced in cervical cancer CaSki, HeLa [human papillomavirus (HPV)-18-positive], SiHa (HPV-16-positive) and C-33A (HPV-negative) cell lines compared with the human keratinocyte HaCaT cell line. Overexpression of p68 induced an elongated and spindle-shaped morphology in CaSki cells. Upregulation of p68 increased the expression of α-smooth muscle actin, vimentin and fibronectin however, epithelial marker E-cadherin was significantly decreased. Furthermore, the in vitro scratch assay demonstrated that overexpression of p68 markedly enhanced CaSki cell migration capacity at 24 and 48 h. Knockdown of p68 partially reversed transforming growth factor-β1 (TGF-β1)-induced changes in epithelial-mesenchymal transition (EMT) markers and cell morphological changes. In summary, the present study demonstrated that p68 transcriptionally activated the expression of TGF-β1, thereby prompting EMT in cervical cancer cells. [ABSTRACT FROM AUTHOR]