# A X-Band Integrated Passive Device Structure Based on TMV-Embedded FOWLP

## TL;DR

This paper presents a new X-band radar component using a cost-effective packaging method, achieving good performance and miniaturization.

## Contribution

A novel IPD structure using FOWLP process with transition line and SMPM testing for X-band FMCW radar is introduced.

## Key findings

- The fabricated IPD structure has dimensions of 16.983 × 24.099 × 0.56 mm³.
- The operational bandwidth at 8.5 GHz center frequency is 7.66% with maximum isolation of 33.9 dB.
- The FOWLP process is validated for miniaturizing X-band FMCW radar antennas and passive devices.

## Abstract

In this paper, the fabrication and testing of an integrated passive device (IPD) structure for X-band FMCW radar based on the fan-out wafer-level packaging (FOWLP) process are discussed. First, a transition line structure is added to the IPD structure to increase the upper impedance limit of the substrate, so as to reduce the process implementation difficulty and development cost. Second, the vertical soldered SubMiniature Push-On Micro (SMPM) interfaces testing method is proposed, reducing the testing difficulty of the dual-port structure with the antenna. Finally, the process fabrication as well as testing of the IPD structure are completed. The dimensions of the fabricated structure are 16.983 × 24.099 × 0.56 mm3. Test results show that, with a center frequency of 8.5 GHz, the actual operational bandwidth of the structure reaches 7.66% (8.095–8.74 GHz), with a maximum isolation of 33.9 dB. The bandwidth with isolation greater than 20 dB is 1.76% (8.455–8.605 GHz). The maximum gain at the center frequency is 2.02 dBi. Additionally, experimental uncertainty analysis is performed on different IPD structures, and the measurement results are basically consistent. These results validate the feasibility of the FOWLP process in the miniaturization of X-band FMCW radar antenna and other passive devices.