Embedded vector measurement of RF/microwave circuits in LTCC technology

Abstract

As the number of wireless systems and standards continues to increase, RF hardware re-use is becoming more and more important to reduce cost and size and eliminate unnecessary component redundancy. One way of maximizing RF hardware re-use is to deploy reconfigurable circuits. This is turn relies on embedded vector measurement to ensure the reconfigurable hardware operates as required. Conventional vector measurement techniques require costly and bulky Vector network analyzers or slightly more compact six-port junctions. Both options require the use directional couplers to sample forward and backward traveling waves, which increases their size and limits their suitability for embedding in reconfigurable RF hardware. Non-directional four-port interferometersoffer an alternative solution for embedded vector measurement that is characterized by a very small size, very low coupling, and ease of integration. In the present work, a new 3D 4-port non-directional reflectometer for measuring complex reflection coefficients is proposed. The proposed reflectometer features two optimized non-directional sniffers positioned below a transmission line with buried lines to carry the sniffed signals to power detectors in LTCC technology. Vertical transitions from the buried lines to surface are designed and optimized. 3D electromagnetic field simulations are used to optimize the proposed design in order to obtain the S-parameter of the structure. Two LT5582 power detector circuits with 57 dB dynamic range are used to detect the coupled power. A prototype of the proposed reflectometer is fabricated in LTCC (Ferro L8) in LACIME laboratory and used to measure 45 different complex loads. The obtained results show excellent agreement with VNA measurements showing errors below 0.3 dB for amplitude and below 3° for phase.

Date	8 May 2019
Original language	American English
Awarding Institution	École de technologie supérieure
Supervisor	Ammar B. Kouki (Supervisor)