An FR4‐based dc to 60 GHz substrate integrated suspended line to suspended coplanar waveguide transition

Abstract

An FR4-based dc to 60 GHz transition from substrate integrated suspended line (SISL) to suspended coplanar waveguide (SCPW) is proposed in this letter. The design is fabricated using standard multilayer printed circuit boards (PCB) technology, and the substrates used are all low-cost FR4. Since the whole structure is in the suspended form, the bandwidth of the transition has been expanded three times when compared with the state of art. By using SISL with double-metal layer and patterned substrate, the loss of the transition is further reduced, and the conductor loss and dielectric loss have been individually analyzed. The results show that the proposed backto-back transition has an insertion loss of less than 2.7 dB and a return loss of better than 11.4 dB from dc to 60 GHz.

FR‐4‐based Ka‐band SISL bandpass filters using folded half‐wavelength resonators

“…The dimensions in (Figure 1B) are as follows (units: mm): a 1 = 0.45, b 1 = 1.80, s 1 = 0.54, d 1 = 0.41, offset 1 = 0.2, p 1 = 0.15, pl 1 = 1.4, box_a 1 = 4.24, box_b 1 = 2.03, a 2 = 0.45, b 2 = 1.85, s 21 = 0.45, s 22 = 0.57, d 2 = 0.35, offset 2 = 0.23, p 2 = 0.15, pl 2 = 1, box_a 2 = 5.27, box_b 2 = 2.08. Furthermore, we added coplanar waveguide transitions 14 on both sides of the design to match the standard 50‐Ω ports. The S‐parameters were measured using the vector network analyzer R&S ZVA67, and two SMA connectors were used.…”

“…As shown in Figure 3, when the loss tangent is 0.02, the Q values of the conventional resonator and folded resonator are 317 and 700, respectively, and the Q promotion is 1.2 times, which also explains why this folded structure can make the loss smaller. Furthermore, we added coplanar waveguide transitions 14 on both sides of the design to match the standard 50-Ω ports. The S-parameters were measured using the vector network analyzer R&S ZVA67, and two SMA connectors were used.…”

A W‐Band Broadband Self‐Packaged Compact SISL Tripler using FR4 substrate

“…Meanwhile, the undesired substrate of Sub3 is cut off to reduce the overall loss further. For the convenience of testing, a CPW‐SISL transition 15 is added to the input port, which is unnecessary when integrating with the VCO on the SISL platform. The field‐circuit cosimulation method is employed in the design.…”

“…FR4 substrate is widely used in board-level circuits because of its low price, high mechanical stability and good insulation performance, 12 but it is difficult to be used in high-frequency circuits due to its high loss tangent. Substrate integrated suspended line (SISL) [13][14][15][16] circuits feature low loss using FR4 substrates because almost all the electromagnetic (EM) field is distributed in the lossless air rather than the lossy substrates. 12,13 Using FR4 substrate to design high-frequency circuits will have great advantages in terms of cost, especially in mass production.…”

An active‐passive cascaded bandpass filter with an 88 kHz–1.1 GHz bandwidth on substrate‐integrated suspended line platform

“…A transition structure from CPW to SISL 24 connects the RF input to the external SMA connector for testing. The RF output is routed directly to reserve space for the placement of DC bias leads.…”