Hubert Diez

Miniaturization of Quadrifilar Helix Antennas for space applications

This paper addresses the miniaturization of Quadrifilar Helix Antennas (QHA) for space applications. A new miniaturization technique based on an original combination of a modified fractal shape and a sinusoidal profile is proposed. Experimental and numerical (simulation) results show that the height of Compact QHA (CQHA) may be 70% shorter than the height of classical QHA without significant degradation of antenna performances.

Compact Ka-band telemetry antenna for satellite applications

This paper presents an alternative design for a payload telemetry data subsystem (PTDS) antenna working in ka-band. Our main driver for this antenna design, was to propose a compact concept with no move of the feed during the connection with the ground station. All the steps of the design are described, and the main results are presented (including the first performances measured on a mock-up).

Miniaturization of Compact Quadrifilar Helix Antennas for Telemetry, Tracking and Command Applications

This paper addresses the miniaturization of Quadrifilar Helix Antennas (QHAs) for space applications (VHF Telemetry, Tracking and Command). Several shape miniaturization techniques were presented, and the impact of height reduction is quantified in terms of radiation pattern, gain and phase center. Simulated and experimental results demonstrate that Compact Quadrifilar Helix Antennas (CQHAs) with a height reduced up to 70% reported to the reference QHA can be designed. By using an appropriate optimization method, the impact of the miniaturization on CQHA performances in terms of radiation pattern and polarization purity can be minimized. Moreover, the impact on the gain is quantified, and design rules are reported. Finally a closed-form expression for estimating the gain of CQHAs from the height reduction factor is found.

High efficiency and compact X band feed for Telemetry Applications

This paper presents the design of a compact and high efficiency feed working in dual circular polarization, in X Band (8.0 GHz - 8.45 GHz). This feed was designed for working with a pointing mechanism typically for transmitting to a ground station, data coming from earth observation or science satellite missions. All the design steps are described, and main results are presented (including performances measured on an electrical model).

Experimental Validation of the Feasibility of a Reconfigurable Square Spiral Antenna

This letter focuses on the experimental validation of a new square spiral antenna topology. The proposed topology can operate over an ultrawideband and be reconfigured into an array of smaller square spiral antennas. This offers a good surface efficiency and many advantages like an increase of both gain and directivity, a good circular polarization over the entire bandwidth, and the ability to reconfigure the radiation pattern. In the letter, the experimental validation is given for frozen states.

Compact patch antenna for Automatic Identification System (AIS)

This paper presents a radiating element developed for the space AIS application. This element is a compact sized and reduced mass microstrip patch antenna integrating frequency resonant adjustment devices. Theoretical and experimental results with good agreement are presented.

A new interleaved ultrawideband antenna array

Full paper - This paper presents a new interleaved antenna array based on a reconfigurable square spiral antenna. The reconfiguration into different antenna arrays allows avoiding the problem of grating lobes which is the main problem limiting the bandwidth for an array of UWB antennas.