A Compact Millimeter-Wave Frequency Conversion SOP (System on Package) Module Based on LTCC Technology

A novel compact millimeter-wave system on package (SOP) module is proposed in this paper. To achieve high integration, the 14 layers substrate of module is fabricated with low temperature co-fired ceramic (LTCC) technology, which is advanced in incorporating the passive components in multi-layers, thus realizing the signal vertical propagation for the SOP. The designed SOP covering 30~40 GHz is the core module for the millimeter-wave radar system. When the transmitting state of the system is initiated, the introduced SOP will up mix input intermediate frequency (IF) signal with local signal (LO) to millimeter-wave band. And the received millimeter-wave signal will be down-converted to the IF signal during the receiving state. The SOP integrates two frequency conversion channels and 34 monolithic microwave integrated circuit (MMIC) chips, with final size of 35 mm × 48 mm. In the whole working band, transmitting signal has a power range of 10~13 dBm with out-of-band spurious suppression below 50 dBc, while the channel under receiving has a gain of 11~15 dB with automatic gain control (AGC) of 0~50 dB and 1dB-step. The receiving and transmitting isolation between the two channels are both greater than 40 dB, and the T/R isolation in one channel is better than 40 dB.

I. Introduction

Nowdays, the millimeter wave wideband radar system has great advantages in many applications, such as automotive imaging [1], [2], electronic countermeasure (ECM) [3], [4] and the through-the-wall surveillance [5]. In one hand, the advanced millimeter wave (mmW) technology contributes a lot to the reduction of the size and weight of the active circuits and antenna, in another hand, the wider bandwidth can provide high probability for radar to successfully detect and jam more enemy targets in different frequency bands, and also greatly improve range resolution that allows for the discrimination of the close targets. But due to the dc-offset effect and the leakage of local signal (LO), the homodyne architecture is not fit for the short range application [6], [7]. To address the issue, the heterodyne architecture is widely implemented in a radar system [7], [8]. Accordingly, a variety of internal core components have gained a great deal of research and design including transmit/receive (T/R) modules, antennas and transceivers [9]–[11]. In [9], a dual channels transmit/receive (T/R) module covering 3 to 6 GHz is designed. In [10], a class of broadband mm-wave printed antennas operating over the entire Ka band is described for multiple mm-wave radio service application. And the system architecture, modeling, and design constraints for an ultra-wideband transceiver with very low power consumption are presented in [11].