Berndie Strassner

5.8-GHz circularly polarized rectifying antenna for wireless microwave power transmission

This paper reports a new circularly polarized (CP) high-gain high-efficiency rectifying antenna (rectenna). The CP rectenna can be rotated and still maintain a constant dc output voltage. The high-gain antenna has an advantage of reducing the total number of rectenna elements to cover a fixed area. The rectenna is etched on Rogers Duroid 5870 substrate with /spl epsi//sub r/=2.33 and 10 mil thickness. A high-gain dual-rhombic-loop antenna and a reflecting plane are used to achieve a CP antenna gain of 10.7 dB and a 2:1 voltage standing-wave ratio bandwidth of 10%. The rectennas pattern has an elliptical cross section with orthogonal beamwidths of 40/spl deg/ and 60/spl deg/. The rectenna circuit has a coplanar stripline band-reject filter that suppresses the re-radiated harmonics by 20 dB. A highly efficient Schottky diode is used for RF-to-dc conversion with an efficiency of approximately 80% for an input power level of 100 mW and a load resistance of 250 /spl Omega/.

Wide-band low-loss high-isolation microstrip periodic-stub diplexer for multiple-frequency applications

This paper introduces a three-port microstrip multifrequency diplexer used in a phased-array transceiver system that employs band-stop filters with open-circuited stubs for band selection and separation. The diplexer is designed to take 10, 12, 19, and 21 GHz into port 1 and to separate 10 and 19 GHz to port 2 and 12 and 21 GHz to part 3 with minimal dispersion. The insertion loss for each frequency varies from 0.4 to 3.4 db and the return loss is better than 10 dB. The isolation between channels at the four frequencies is greater than 50 dB. Each passband created between adjacent stopbands has a bandwidth over 1 GHz. The microstrip diplexer is designed using periodic stubs that collectively have the advantages of low insertion loss, high isolation and rejection, wide-band performance on each channel, and easy fabrication. This type of diplexer has many applications in multifrequency transceivers for communication systems.

5.8-GHz circularly polarized dual-rhombic-loop traveling-wave rectifying antenna for low power-density wireless power transmission applications

This paper reports a right-hand circularly polarized (RHCP) high-efficiency traveling-wave rectifying antenna (rectenna) designed in a coplanar stripline (CPS) circuit that is etched on a Rogers Duroid 5870 substrate with /spl epsiv//sub r/=2.2 and 20-mil thickness. A 4 /spl times/ 1 traveling-wave array of RHCP high-gain dual-rhombic-loop antennas (DRLAs) and a reflecting plane are used to provide highly efficient RF-to-DC conversion in the presence of lower power densities regardless of the rectennas broadside orientation. The DRLA array has a circularly polarized antenna gain of 14.6 dB with a 2:1 voltage standing-wave ratio bandwidth of 17% and a better than 3 dB axial ratio fractional bandwidth of 7% centered about 5.8 GHz. The rectenna achieves 82% RF-to-DC conversion efficiency at 5.8 GHz and uses a low-profile CPS band-reject filter to suppress the re-radiated second harmonic by over 14 dB. The rectenna operating at low power density should have many applications when the transmitting power is low and/or the transmission distance is long.

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.

Circularly polarized reflectarray with microstrip ring elements having variable rotation angles

This paper reports a 0.5-m-diameter right-hand circularly polarized planar reflecting antenna array that uses 437 printed microstrip ring elements of variable rotations to achieve cophasal far-field radiation and wide-band performance at a focal length of 0.35 m. The array is etched on Rogers Duroid 5870 substrate with /spl epsiv//sub r/= 2.33 and 0.508-mm thickness. At 7.1 GHz, the reflectarray achieves an efficiency of 41.7% with a gain at broadside of 27.6 dB. Sidelobe suppression is greater than 17.3 dB, and the left-hand cross-polarization is 23.2 dB below the desired right-hand component. The best efficiency of 45.7% and the maximum gain of 28.2 dB occur at 7.3 GHz.

Highly efficient C-band circularly polarized rectifying antenna array for wireless microwave power transmission

This paper reports a new circularly polarized (CP) high-gain, high-efficiency rectifying antenna (rectenna) array designed in a coplanar stripline (CPS) circuit. The array can maintain a constant dc output voltage regardless of its broadside orientation. The array is etched on Rogers Duroid 5870 substrate with /spl epsiv//sub r/=2.33 and 10 mil thickness. High-gain dual rhombic loop antennas and a reflecting plane are used in order to reduce the total number of rectenna elements necessary to cover a fixed area. Each antenna has a CP antenna gain of 11 dB and a better than 1 dB axial ratio fractional bandwidth of 4.7%. The single element rectenna achieves 81% RF-to-dc coversion efficiency at 5.71 GHz and uses a CPS band-reject filter (BRF) to suppress the reradiated harmonics by more than 19 dB. At 5.61 GHz, using an array loading of 150 /spl Omega/, a 3 /spl times/ 3 rectenna array produces 0.86 W of dc output power with an RF-to-dc conversion efficiency of 78% and an axial ratio of 0.25 dB for an incident CP power density of 7.6 mW/cm/sup 2/.

Integrated antenna system for wireless RFID tag in monitoring oil drill pipe

The paper reports a new integrated antenna system for a 5.8 GHz radio frequency identification (RFID) tag proposed for predicting the pipes lifetime and to provide inventory control. Powering for the tags electronics is obtained by using rectifying circuits that convert microwave energy into DC energy. The tag requires a minimal incident power density of 13.5 mW/cm/sup 2/ to establish a link and transmit 64-bit coded information to the interrogating reader.

New wide-band DC-block cymbal bandpass filter

A new low-loss dc-blocking parallel-cascaded bandpass filter is presented. The filter is much easier to use and fabricate, more compact, and simpler to design than the conventional end- or parallel-coupled line filters. The filter has a wide passband with a 2:1 voltage standing-wave ratio bandwidth of around 10% and an insertion loss of 0.5 dB at 10 GHz. Simulated results agree very well with experimental results.

A circularly polarized rectifying antenna array for wireless microwave power transmission with over 78% efficiency

This paper reports a new circularly polarized (CP) high gain, high-efficiency rectifying antenna (rectenna) array designed in a coplanar stripline circuit. The array can maintain a constant DC output voltage regardless of its broadside orientation. Each antenna has a CP antenna gain of 11 dB and a better than 1 dB axial ratio fractional bandwidth of 4.7%. Coplanar stripline (CPS) band-reject filters (BRF) are used to suppress the re-radiated harmonics by more than 19 dB. At 5.61 GHz, using an array loading of 150 /spl Omega/, a 3/spl times/3 rectenna array achieves an RF-to-DC conversion efficiency of 78% and an axial ratio of 0.25 dB.

5.8 GHz circular polarized rectifying antenna for microwave power transmission

This paper reports a new 5.8 GHz circular polarized (CP) high gain, high-efficiency rectifying antenna (rectenna). The CP rectenna can be rotated and still maintain a constant output voltage. A high-gain dual rhombic loop antenna and a reflecting plane are used to achieve a circular polarized antenna gain of 10.5 dB, a 2:1 VSWR bandwidth of 10 %, and average beamwidths of 43/spl deg/ and 59/spl deg/ In the E- and H-planes, respectively. The rectenna circuit has a coplanar stripline (CPS) band reject filter (BRF) which suppresses the re-radiated harmonics by 20 dB. A highly efficient Schottky diode is used for RF to DC conversion with an efficiency of approximately 80%.