Christopher T. Rodenbeck

A C/ka dual frequency dual Layer circularly polarized reflectarray antenna with microstrip ring elements

This paper reports a dual frequency dual layer circularly polarized reflectarray operating in the C and Ka bands. A 0.5-m right-hand circularly polarized planar reflectarray antenna is designed using microstrip ring elements of variable rotations to achieve a cophasal beam at broadside. The microstrip ring elements are more compact than the traditional reflectarray elements and can minimize blockage for the multilayer multifrequency applications. The highest efficiencies measured are 46% at 7.3 GHz and 38% at 31.75 GHz. The tested cross-polarization levels are -21 dB at 7.3 GHz and -29.2 dB at 31.75 GHz at the broadside direction. The tested results show that the designed ring element is suitable for both the single and dual layer applications with good bandwidth and circularly polarized performance.

Ultra-wideband low-cost phased-array radars

Emerging radar applications require phased arrays that can operate over wide bandwidths to support multiband/multifunction operation. In response to that need, this paper presents a cost-effective implementation for extremely wide-band phased-array radars. Two designs are demonstrated, one operating from 3 to 12 GHz and the other operating from 8 to 20 GHz. These designs incorporate ultra-wideband antipodal tapered slot antennas, a novel cross-polarization suppressed array architecture, piezoelectric true-time-delay phase shifters, and broad-band high-power monolithic amplifiers. The resulting systems provide target detection and beam steering over the complete operating bandwidths. These results exceed the state-of-the-art for phased-array radars in terms of bandwidth and cost and should have direct applications in the development of ultra-wideband and multifunction radar systems.

Development of a retrodirective wireless microwave power transmission system

This paper describes the design of a small-scale system for demonstrating retrodirective wireless power transmission. A solid-state phased array transmitter with retrodirective control drives two 5.8 GHz circular-polarized (CP) transmit antenna subarrays that illuminate a remote CP rectenna array. The total power transmitted is about 40 W. A 2.9 GHz pilot beam projected from the rectenna site is received at the transmit site and processed for retrodirective control of the 5.8 GHz transmitter.

Novel low-cost beam-steering techniques

This paper summarizes and compares several 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) and a movable grating film fed by dielectric image line. 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.

A phased-array architecture for retrodirective microwave power transmission from the space solar power satellite

This paper presents a phased array architecture for retrodirective microwave wireless power transmission from the space solar power satellite (SPS). The proposed architecture uses a 2.9-GHz pilot beam and a 5.8-GHz transmit beam, with retrodirective phasing implemented directly at RF. Experimental and theoretical results are given to validate the approach.

A 10- to 21-GHz, low-cost, multifrequency, and full-duplex phased-array antenna system

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), 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/spl deg/. Using dual-aligned PETS for bidirectional phase shifting results in wide scan angles of 38.6/spl deg/, 37.6/spl deg/, 43/spl deg/, and 40/spl deg/ 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.

A novel millimeter-wave beam-steering technique using a dielectric-image line-fed grating film

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/spl deg/ scanning reported at 35 GHz. Theoretical calculations closely predict the observed scan angle across the entire range of measurement.

A multiband, compact, and full-duplex beam scanning antenna transceiver system operating from 10 to 35 GHz

This paper presents a compact phased-array antenna transceiver system that can operate over a wide bandwidth from 10 to 35 GHz with the abilities of beam scanning and full-duplex communication. The system consists of ultrawide-band Vivaldi antennas, a multiline PET-based phase shifter, a six-channel microstrip multiplexer, and monolithic microwave integrated circuit (MMIC) amplifiers. The multiplexer routes 10, 19, and 32 GHz signals to the transmit path and 12, 21, and 35 GHz signals to the receive path. The multiplexer shows insertion loss between 2.2 and 3.4 dB for all six channels and together with wide-band MMIC amplifiers plays an important role to build a compact, multifrequency, and full-duplex transceiver system. The system should have many applications in multiband satellite communication systems and radar systems.

A limitation on the small-scale demonstration of retrodirective microwave power transmission from the solar power satellite

The solar power satellite (SPS) is a future system for transmitting a high-power microwave beam to the Earth using a large, space-based retrodirective array. However, the small-scale demonstration of a prototype retrodirective transmitter for this application faces a basic limitation and associated tradeoffs, which are identified and described in this paper. Computer-simulated examples are presented, and recommendations are made.

Circular-polarized reconfigurable grating antenna for low-cost Millimeter-wave beam-steering

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/spl deg/ 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.