Ivan Flammia

Novel E-Band (71–76 GHz) photodiode module featuring a hermetic grounded-coplanar-waveguide-to-rectangular-waveguide transition

This paper presents a novel concept of a hermetic E-Band Photodiode (PD) Transmitting Module for Radio-over-Fiber (RoF) applications. A commercial PD chip with 50 Ω coplanar waveguide (CPW) output is wire-bonded to a 50 Ω grounded coplanar waveguide (GCPW) based on ROGERS RT/Duroid 5880 substrate. From the GCPW board a hermetic transition that makes use of a double-slot coupling approach is designed and optimized for the 71–76 GHz band. This concept allows to efficiently coupling the electrical power delivered by the PD chip to a Rectangular Waveguide WR-12 output with an insertion loss of only 3 dB.

Robust 71–76 GHz radio-over-fiber wireless link with high-dynamic range photonic assisted transmitter and laser phase-noise insensitive SBD receiver

This paper describes a robust radio-over-fiber wireless link system for use in wireless extension and mobile backhaul applications. The wireless link operates at 71-75 GHz E-band carrier frequencies and can transmit ultra-high access data such as Gigabit Ethernet or OC-48 up to 2.5 Gbps. Enabling photonic technologies, system configurations, and lab trials are presented.

A novel transition from grounded coplanar waveguide to substrate inte grated waveguide for 60 GHz Radio-over-Fiber photonic transmitters

We present a novel transition from grounded coplanar waveguide (GCPW) to substrate integrated waveguide (SIW), designed on a ROGERS 5880 laminate for 60 GHz Radio-over-Fiber (RoF) photonic transmitters. The transition serves as connection between a 60 GHz photodiode (PD) chip and a suitable SIW antenna. In contrast to previous designs, our approach makes use of a quarter-wave coupled-lines (CL) section to transfer the signal carried by the GCPW to the SIW. This technique, creating a DC-block between the GCPW signal track and the ground layers, allows for correctly biasing the PD. In order to reduce the propagation of parasitic modes as well as the risk of interferences, the transition is fully enclosed by a fence of via holes. Simulations show that in the whole 57-64 GHz band, the return loss (RL) is higher than 17 dB, while the insertion loss (IL) is ~ 0.4 dB. To prevent the loss of RF power through the DC path, a planar RF-choke (RL > 22 dB, IL <; 0.4 dB and RF-to-DC isolation (IS) higher than 28 dB) is additionally integrated.

Planar 71–76 GHz laminate integration platform for connecting millimeter wave photodiodes to WR-12 waveguides

Here, a millimeter wave photodiode (mm-wave PD) integration platform for development of high-power Radio-over-Fiber (RoF) wireless photonic transmitters (PTs) is presented. The platform features a novel planar bias-tee network design making use of a single quarter-wave coupled-line (CL) technique and two slotted split-ring resonators (SRRs) integrated in the DC bias line. The introduced bias-tee network enables proper biasing for mm-wave PDs, e.g. the triple transit region photodiode (TTR-PD), and protects the hybrid integrated RF amplifier from being damaged by the bias voltage. The 3D full-wave electromagnetic field simulations of the designed bias-tee network show that in the whole 71-76 GHz band, the return loss (RL) is higher than 20 dB, the RF signal suppression level (IS) is higher than 30 dB, while the insertion loss (IL) is lower than 0.6 dB. A fence of via holes surrounds the bias-tee network to reduce the RF propagation losses into the laminate and to ensure that the grounded coplanar waveguide (GCPW) supports only a quasi-static transverse electromagnetic mode (TEM). The bias-tee network integrated together with high-electron-mobility transistor (HEMT) RF amplifiers and GCPW-to-rectangular waveguide (WR) transition enables the development of high-power (>17 dBm) PTs with WR-12 output. The IL of the complete integration platform is ~2.2 dB.

Planar bias-tee circuit using single coupled-line approach for 71–76 GHz photonic transmitters

This paper presents a novel planar bias-tee (BT) circuit comprising a quarter-wave single coupled-line (SCL) section designed on 127 μm thick ROGERS RT/duroid 5880 laminate for E-band (71-76 GHz) wireless photonic transmitters. The BT circuit enables proper biasing for millimeter wave photodiodes (mm-wave PDs) through the RF-choke, and in addition, protects the hybrid integrated RF amplifier from being damaged by the DC voltage using the SCL DC-block. The planar RF-chock design is based upon two slotted split-ring resonators (SRRs) and is integrated in the DC bias line in order to prevent the leak of the RF signal into the voltage circuitry. Numerical results of the DC-block section show that in the entire 71-76 GHz band, the return loss (RL) is higher than 36 dB while the insertion loss (IL) is lower than 0.4 dB. The overall performance of the complete BT circuit (DC-block and RF-choke) has been calculated by the 3D full-wave electromagnetic field simulator based on the finite element method (RL > 20 dB, IL <; 0.6 dB and RF signal suppression in the DC bias line (IS) > 30 dB). A via hole fencing surrounds the BT circuit to reduce the RF propagation losses into the laminate and to ensure that the grounded coplanar waveguide (GCPW) supports only a quasi-static TEM mode.

Compact transmitter and receiver modules for E-band wireless links

Compact wireless Radio-over-Fiber transmitter and receiver modules for 1.025 Gb/s wireless communication in the frequency range of 71-76 GHz.

Novel Quasi-Hermetic Photodiode Module Featuring an E-Band Rectangular Waveguide (WR-12) Output

A quasi-hermetic photodiode module featuring a WR-12 rectangular waveguide (RW) output has been developed for operation in the E-band. The module makes use of a grounded coplanar-waveguide-to-rectangular-waveguide transition implemented on a Rogers RT/duroid 5880 laminate that does not require any mechanical modifications of the RW. Simulations show that the transition has excellent radio frequency (RF) characteristics (return loss larger than 30 dB, insertion loss smaller than 2 dB, maximum group delay deviation smaller than 1 ps). Measurements confirm the simulated results and highlight the importance of via-holes to reduce the overall loss. The maximum output power delivered by the module, at a DC photocurrent of 10 mA, is -12.5dBm. At 73 GHz, the 1-dB compression point is found to be at a photocurrent of ~ 9mA, with an RF output power of ~ -13.5dBm . The measured output power has less than 1 dB ripple in the frequency range of interest.