Uniplanar Design Research Articles

COPLANAR RING DIVIDER WITH WIDEBAND HIGH ISOLATION PERFORMANCE

In this letter, the design and measurement of a new ring power divider exhibiting wideband high isolation is presented. Coplanar techniques are used to achieve a compact and truly uniplanar design. The design is demonstrated by a prototype, operating at K- band, that has been monolithically fabricated using a GaAs MMIC process with airbridge technology. The measured insertion loss is 0.6dB at the center design frequency of 25GHz. The output port isolation is better than 20dB across a wide bandwidth from 10MHz to 50GHz. The output amplitude and phase balance is within §0:5dB and §2 - , respectively, in the bandwidth from 10MHz to 43GHz.

Biomechanical Differences between Two Exoprosthetic Hip Joint Systems during Level Walking

Previous studies have shown low end-user acceptance of a hip disarticulation style prosthesis and that the limitations of such prostheses, including poor gait pattern, socket discomfort, weight of the prosthesis, loss of mobility, instability and high energy consumption are a contributing factor. This study was initiated to determine if a new style of prosthetic hip joint could help to overcome some of the limitations concerning the gait pattern. The present study analyzed the gait pattern of six hip disarticulation amputee subjects. The objective was to compare two different prosthetic hip joints, both from Otto Bock HealthCare: The new Helix(3D) and the 7E7, which is based on the Canadian model proposed by McLaurin (1954). Kinematics and kinetics were recorded by an optoelectronic camera system with six CCD cameras and two force plates. During weight acceptance, the Helix(3D) extends considerably slower and reaches full extension later than the 7E7. The increased range of pelvic tilt observed with hip disarticulation amputees is significantly reduced (by 5 ± 3 degrees) when using the Helix(3D) Hip Joint. In addition, this system showed increased stance phase knee joint flexion as well as increased maximum swing phase knee flexion angles compared to the 7E7. These motion analysis results show that the Helix(3D) Hip Joint can reduce gait abnormalities compared to the uniplanar design of the 7E7 hip joint.

Two-Dimensional Planar Array for Digital Beamforming and Direction-of-Arrival Estimations

A compact uniplanar design of 2-D antenna arrays is presented for digital beamforming (DBF) and direction-of-arrival (DOA) estimations. The array is based on switchable microstrip slot antennas that are series fed in one dimension and parallel fed in the other dimension. In conjunction with spatial multiplexing of local elements (SMILE) techniques, the array is able to use both the series- and parallel-fed antennas for 2-D beamforming and DOA estimations. The combination of series and parallel feeding provides a simple way of constructing 2-D DBF arrays with a simple and uniplanar feed network. Other advantages are its low cost and compatibility with a microwave integrated circuit process for the receiver system. A 4 times 4 receiving array test bed at a 5.5-GHz operating frequency is fabricated, and DBF and DOA tests on this test bed are successfully demonstrated.

Slot line FED dipole antenna for wide band applications

AbstractA slot line fed planar dipole antenna with a parasitic strip for wide band applications is presented. The presented antenna offers a 2:1 VSWR bandwidth from 1.66 to 2.71 GHz covering the DCS/PCS/UMTS and IEEE 802.11b/g bands with a gain better than 6.5 dBi. The uniplanar design, simple feeding, and high gain make it a versatile antenna for wireless applications. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 826–830, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24184

Compact Asymmetric Coplanar Strip Fed Monopole Antenna for Multiband Applications

A compact asymmetric coplanar strip fed monopole antenna for multiband applications is presented. The antenna exhibits three resonances around 1.8, 2.4, and 5.6 GHz covering the DCS/PCS/UMTS/IEEE 802.11b/g/IEEE802.11a/HIPERLAN2 bands. The multiband characteristic of the antenna is due to the various meandered current paths excited in the radiating structure. The antenna has an overall dimension of only 2830 when printed on a substrate of dielectric constant 4.4. The uniplanar design, simple feeding technique and compactness make it easy for the integration of the antenna into circuit boards. Details of the antenna design, experimental and simulated results are presented and discussed.

A broad-band balanced HEMT frequency doubler in uniplanar technology

Design and performance of a simple balanced high electron-mobility transistor doubler in uniplanar technology are described. The uniplanar in-phase and out-of-phase T-junctions with 2-octave bandwidth and a hybrid ring coupler with more than octave bandwidth have also been developed and investigated as a part of the doubler circuits. Measurements show more than 3-dB conversion gain, effective fundamental- and odd-harmonics suppression (>25 dB) in octave bandwidth (output frequency from 6 to 12 GHz), and maximum conversion gain of 8.8 dB at 3-dBm-input power level. The uniplanar design and simplicity of the circuit itself make the proposed frequency doubler suitable for monolithic-microwave integrated-circuit fabrication in millimeter-wave range.